Bake for about 12-15 minutes until brown. Remove from the oven and allow to cool slighty.
Place sheet pans in the freezer for about 12 minutes to firm to prevent spreading during baking.
Scoop 1 teaspoon of dough and then roll in between the palms of your hands until a ball, about the size of a walnut, has formed. Drop onto a cookie sheet. Press your thumb into the center of the dough ball to form a slight well. Repeat until all dough has been used.
Combine butter and sugar until creamy. Add in vanilla and egg until well-incorporated and then slowly add flour, baking powder, and salt. Shape dough into a ball. Cut into fourths and wrap each section tightly with plastic wrap and store in the refrigerator.