Blend strawberries until smooth.
Add water, sugar, and strawberries in a heavy based saucepan
Cook on low until the strawberries are cooked completely.
Add the vanilla extract (if using)
Strain thru a sieve
Pour into a clean bowl
Chill in the fridge until completely cold and thick
When the strawberry mousse domes are firm
Invert the silicon molds to remove them from the mold
Place each dome on the prepared hazelnut cookie crust
Top with a teaspoon of thick strawberry coulis - Alternatively you can glaze the whole dome with a pouring consistency strawberry coulis before you place it on the cookie crust.
Garnish with a slice of strawberry or mint leaf.
Let thaw in the fridge for an hour before you serve so the mousse is soft not frozen.