2 large eggs
1 cup sugar
4 cup all-purpose flour
1 teaspoon baking powder
3 sticks salted butter; softened
1/2 cup sugar cubes; coarsely crushed,
Beat together 1 egg and sugar with an electric mixer until thick and pale. Sift in flour and baking powder and add butter. Beat on low speed until mixture forms a dough. Chill, wrapped in plastic wrap, until firm, at least 1 hour.
Preheat oven to 350F.
Lightly beat remaining egg. Roll level teaspoons of dough into balls and arrange 1 inch apart on ungreased baking sheets. Press thumb into center of each ball to flatten, leaving a depression, and brush lightly with egg.
Sprinkle crushed sugar in centers and bake in batches in middle of oven until golden, 12 to 18 minutes. Transfer to racks to cool completely.
Source: Gourmet December 1999