Preheat oven at 170C/ 340 F
Grease and line with parchment an 8 x 8-inch square cake pan
Combine the flour, cornstarch, and salt. Set aside
Cream butter and powder sugar until smooth
Add the egg - combine well
Followed by the molasses and vanilla
Lastly, add in the flour mixture.
Spread in the prepared baking tray
Use a fork to score fork marks on the top
Bak in a preheated oven for 25 to 35 minutes until the edges start to get lightly golden.
Cool in the pan for 10 minutes then move to a cooling rack.
While shortbread is slightly warm cut into smaller pieces.
When cooled store in a cookie jar
These will stay good for up to 2 weeks.