This is my Scottish grandmother's recipe. It melts in your mouth rather than be hard and crunchy like the North American version.
- Sift cornstarch, sugar and flour together.
- Blend in butter until combined and then use hands to knead into a soft dough.
- Shape dough into a ball, cover with plastic wrap and refrigerate for 30 minutes.
- Place dough in the bottom of a greased 9x9-inch pan and bake at 300°F for 15-20 minutes or until lightly browned.
- Cool completely in pan and cut into squares.
- Store in an airtight container.