Ermine Frosting, Boiled Milk or Flour Frosting (video recipe)

Name: Ermine Frosting - Boiled Milk Frosting
Prep time: 15 min
Cook time: 5 min
Total time: 620 min
Ingredients: 1 cup Sugar; 1/2 cup All-purpose flour; 1/4 tsp Salt; 2/3 cup Milk (full-fat); 8 oz Butter; 1 tsp Vanilla Extract

Recipe Video Print Pin Recipe

Ermine frosting is made by cooking milk, sugar, and flour into a roux. This roux is then added to whipped butter, which creates a rich and creamy, yet light, airy, and fluffy buttercream that is less sweet than traditional buttercreams.

A white wedding cake. — Frosting Made with boiled milk roux called Ermine

Table of Content

Why make this frosting
Ingredients and substitutes
Easy ermine buttercream frosting
Frosting a cake
Tips for Success
What can you do with this frosting?
More frosting recipes
You may also like
Printable Recipe
Join the conversation

Often referred to as boiled milk frosting, roux frosting, or flour frosting, this is no new buttercream. In fact, it has been here for many years. But, recently has gained some renewed popularity.

So, yes, this is an old-fashion buttercream. I grew up calling this boiled flour frosting until I became a professional cake decorator. My mom would make this for cupcakes. In fact, it was often her default for cupcakes. Because it is light, airy, very fluffy, and best of all, less sweet than American buttercream.

Why make this frosting

It's one of the less sweet buttercreams you can make!
The process may sound weird, but if you've made a roux, pudding, or custard before, then it's very similar. Cooking the flour mixture with milk, sugar, and flour becomes a thickening agent that then emulsifies with the butter to create this creamy, velvet-like light and airy frosting.
And unlike meringue buttercream, this one does not have eggs, so it's also an eggless frosting.
Today, I am frosting my white cake recipe with it. And yet, you can use this on any of my cupcakes or cake recipes. Red velvet cake while perfect with cream cheese frosting is absolutely delicious with this frosting and so is my moist chocolate cake. So, here's another addition to my 50 plus frosting recipes on this blog.
And you can also replace some of the butter in this frosting with cream cheese to make a cream cheese ermine frosting.

Boiled flour frosting in a stand mixer. — Frosting Made with boiled milk roux called Ermine

Ingredients and substitutes

Butter - I always use unsalted butter and butter that is white in color. The color of your frosting will depend on the color of the butter.
Sugar - This frosting is less sweet than regular frosting. But you can add up to ½ cup additional sugar. Alternatively, you can taste the buttercream and add a few tablespoons of powdered sugar to bring to your taste.
Flour - I am using all-purpose flour. I think that works best for this.
Milk - I like to use whole milk of about 3%. Using low-fat milk will make a very thin consistency buttercream, which might not be easy to spread.
Flavoring - a teaspoon of vanilla extract is a must for me. But, you can also add almond extract, rose extract, or orange extract.

Ingredients to make Cooked flour frosting Ermine. — White Frosting Made with boiled milk roux called Ermine

Easy ermine buttercream frosting

Make the roux - In a saucepan, combine sugar, flour, salt, and milk. Place over medium heat stirring constantly.
Pro tip - Before you place it on heat, use a whisk to ensure you have no lumps in the milk. Otherwise, the roux will be lumpy.
Cook until you have a thick smooth paste for about 5 to 7 mins. Then, remove from heat and transfer to a cool bowl.
Pro tip - Transferring to a clean bowl will ensure the mixture stops cooking and prevent lumps.

Progress pictures making roux for Ermine frosting. — Frosting Made with boiled milk roux called Ermine

Next, cover with plastic wrap making sure the plastic touches the top surface of the roux. Then, set aside to cool completely.
Pro tip - Roux like this can crust and form a skin very quickly similar to custard. And that can be very lumpy later in the frosting. So, cover immediately.
In the bowl of a stand mixer with the whisk attachment on medium speed, cream the butter for a minute until light and fluffy.
Pro tip - When whipped, the butter will turn lighter in color as more air will be incorporated into it.
Gradually, add the cooled roux - one tablespoon at a time. Make sure to scrape the sides of the bowl for any butter stuck to the bowl.

Progress pictures making the Ermine frosting. — white Frosting Made with boiled milk roux called Ermine

Once all the milk paste/roux has been added, whip the buttercream on medium-high speed for 2 full minutes until light and fluffy.
Pro tip - It is important to whip the buttercream so you have a consistency similar to whipped cream. Otherwise, it mixture will be very soft and won't be easy to frost.
Finally, add the vanilla extract and any other flavoring if desired.

Frosting a cake

This frosting is best used when just made as it's smooth and creamy.
And if it is too soft, place it in the fridge for a few minutes, then re-whip it again.
Also, use an offset spatula for the top and a bench scraper to smooth the sides of the cake.

Whipping Ermine frosting in a stand mixer. — Easy Frosting Made with boiled milk roux called Ermine

Tips for Success

Cook the milk paste on medium-low heat so the milk does not get burnt. Burt milk frosting does not taste good.
You want the flour paste to cook until thick like toothpaste consistency. If it is too liquid the frosting will be soft and not hold up.
Use room temperature butter but not too soft. You want the butter to whip creamy consistency so the paste will emulsify and not break
Curdles frosting - This can happen in a few circumstances: If you add warm roux to cold butter it will curdle not cream.
Also, if you add cold roux to cold butter it will result in curdling. Work at a similar temperature.
And, of course, if they try to re-whip cold frosting it will curdle because this one has flour which kinda sets the buttercream.
Greasy frosting - Adding a warm roux to warm butter will cause the frosting to become greasy. Chill it then re-whip it.
What you can and cannot do with Ermine frosting. You can use it to fill and frost cakes and cupcakes
It works great to pipe borders and patterns on the cake
But, you cannot pipe buttercream flowers as the frosting is too soft. For that, you will still have to use my stiff buttercream for making flowers
Ermine frosting is perfect on the day it is made. After that, the flour in the frosting thickens and you end up with lumpy frosting.
This is not the frosting to use under fondant. It's too soft even after you chill it, it does not become hard.

A white wedding cake on a cake stand. — Frosting Made with boiled milk roux called Ermine

What can you do with this frosting?

There is so much you can do with ermine frosting. And yet, there are limitations to its uses. For example:

You can use it to fill and frost cakes and cupcakes.
It also works great to pipe borders and patterns on the cake.
But, you cannot pipe buttercream flowers as the frosting is too soft. For that, you will still have to use my stiff buttercream for making flowers.
Also, Ermine frosting is perfect on the day it is made. After that, the flour in the frosting thickens and you end up with lumpy frosting.
However, this is not the frosting to use under fondant. It's too soft even after you chill it it does not become hard.

A white layer cake being sliced on a cake stand. — White Vanilla Cake with Ermine Frosting

How to flavor Ermine frosting

The frosting is soft, so it's best to use fruit powders instead of fruit purees.

Chocolate - Add 2 tablespoon cocoa powder to make a chocolate Ermine frosting. Add at the end of the whipping.
Add 2 tablespoon fruit powder such as strawberry, raspberry, and berry at the end of the final whipping.
Peanut butter - You can use ¼ cup peanut butter but it will make the frosting softer.
Others - You can add 50 grams of melted chocolate, ¼ cup caramel sauce, dulce de leche, and lemon curd. It will make the frosting softer (still delicious).

A white wedding cake on a cake stand with a slice of the cake on a plate. — Frosting Made with boiled milk roux called Ermine

How much buttercream frosting do I need for my cake?

This is a general guide I use for my cakes. Note I have given you the filling and frosting separately so you can choose to use another filling with your buttercream. If you choose to fill and frost the cake with this - you can use the last column/total. The amount is in cups - 1 kgs frosting makes about 8 cups

Round	Square	Layers	Filling	Frosting	Total
6-inch	5-inch	2	1.5 C	2.5 C	4.5 C
8-inch	6-inch	2	2 C	4 C	6 C
9-inch	7-inch	2	2.5 C	5 C	7.5 C
10-inch	8-inch	2	3 C	6 C	9 C
12-inch	10-inch	2	5 C	8 C	13 C
14-inch	12-inch	2	7 C	10 C	17 C
Sheet	9x13x2	1	2 C	5 C	12 C
Tube	9-inch	1		4 C	4 C
Cupcake		12		3 C	3 C

Frost the cake with Ermine frosting — Best White Vanilla Cake with Ermine Frosting

More frosting recipes

How long will this Ermine frosting keep?

Once frosted, the cakes and cupcakes with Ermine frosting will keep in the fridge for three to four days. And the frosting itself will keep in the fridge for up to a week. However, you will need to bring it to room temperature and re-whip it.

What does ermine frosting taste like?

Absolutely delicious. It has the texture of whipped cream. Smooth, creamy, and yet light, airy, and fluffy. And the best part is, that it is less sweet than traditional frostings. But, you certainly can add a little more sugar if you want.

Can I freeze this frosting?

I believe you can freeze this frosting for up to a month in freezer-safe bags. However, you will need to thaw it in the fridge overnight and then re-whip it before using it.

Can I make the roux/milk paste in advance?

Yes, you can make the milk paste or roux up to 2 days in advance. But, make sure to cover with a cling wrap touching the surface of the roux to prevent skin from forming.

My Ermine frosting is too soft? Why is my ermine buttercream runny?

If the butter is too soft or the roux is too warm, it will cause the butter to melt and become soft. This often happens in hot and humid conditions. But, don't worry, just place it in the fridge for a few minutes, then, re-whip again. And depending on how warm the mixture gets, you may need to chill it a few times. Another reason it can be soft is if you have not cooked the roux until it's thick. A very liquid roux can make the buttercream soft. For example, see the consistency of the roux in the image below. This is what you want.

How do you thicken ermine frosting?

First, let the buttercream cool for a while. This will let the starch in the buttercream cool, which in turn helps it thicken. Then, whip until light and fluffy.

Printable Recipe

Ermine Frosting - Boiled Milk Frosting

Author: Veena Azmanov

4.95 from 20 votes

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Prep Time: 15 mins

Cook Time: 5 mins

Cooling time: 10 hrs

Total Time: 10 hrs 20 mins

Difficulty: Easy

Calories: 228kcal

Adjust Servings Here: 4 cups

Description

Ermine Frosting is made by cooking milk, sugar, and flour into a roux. This roux is then added to whipped butter, which creates a rich and creamy, yet light, airy, and fluffy buttercream that is less sweet than traditional buttercreams.

Video

Conversions Used

1 lb = 453 grams, 1 cup = 240 ml, 1 stick = 113g, 1 tbsp= 15 ml, 1 tsp= 5 ml,

Ingredients

Enough for 12 cupcakes or 2 x 6-inch layer cake

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Instructions

Make the roux - In a saucepan, combine sugar, flour, salt, and milk. Place over medium heat stirring constantly.
Pro tip - before you place on heat use a whisk to ensure you have no lump in the milk. Otherwise, the roux will be lumpy.
Cook until you have a thick smooth paste about 5 to 7 mins. Remove from heat and transfer to a cool bowl.
Pro tip - transferring to a clean bowl will ensure the mixture stops cooking and prevent lumps.
Cover with plastic wrap making sure the plastic touches the top surface of the roux. Set aside to cool completely.
Pro tip - roux like this can crust and form a skin very quickly similar to custard which can be very lumpy later in the frosting so cover immediately.
In the bowl of a stand mixer with the whisk attachment, cream the butter for a minute speed until light and fluffy.
Pro tip - when whipped the butter will become lighter in color as air will be incorporated into it.
Gradually add the cooled roux - one tablespoon at a time. Making sure to scrape the sides of the bowl for any butter stuck to the bowl.
Once all the milk paste/roux has been added, whip the buttercream on medium-high speed for 2 full minutes until light and fluffy.
Pro tip- it is important to whip the buttercream so you have a consistency similar to whipped cream. Otherwise it mixture will be very soft and won't be easy to frost.
Finally, add the vanilla extract and any other flavoring if desired.