This is a traditional English recipe.
3 sticks of butter, room temperature
3 cups flour
1 cup corn starch
1 cup powdered sugar
1/2 teaspoon baking powder
a pinch of salt
Mix all dry ingredients together, set aside. In a separate bowl, cream butter. Add dry ingredients and mix. The dough should be soft, smooth, and kneadable. Mixing by hand, the dough may remain slightly crumbly. Using a mixture will make the dough smoother. Press dough into a ungreased pan and smooth dough. Prick with a fork. Bake 30 to 40 minutes at 325 degrees. When slightly brown, remove from oven and cut into desired pieces while still hot. Cool and store in airtight container or freeze until desired use. Recipe may be used in shortbread clay molds.