1 cup butter, at room temperature
1 cup sugar
1 large egg
1/2 tsp almond extract
2 1/2 cups all-purpose flour
1 tsp baking powder
1 large egg yolk
1 tbsp milk
1/3 cup blanched whole almonds
2 tbsp sesame seeds
1. In a large bowl, with an electric mixer on medium speed, beat butter and sugar until smooth. Add whole egg and almond extract and beat until well blended. Stir or beat in flour and baking powder until well blended. Cover bowl and chill until dough is firm, about 1 hour.
2. Shape dough into 1-inch balls, flatten each slightly, and place each about 1 inch apart on buttered or cooking parchment-lined 12- by 15-inch baking sheets.
3. In a small bowl, beat egg yolk with milk to blend. Brush cookies lightly with egg mixture; discard any remaining. Press an almond into the center of each cookie and sprinkle each with about 1/8 teaspoon sesame seeds.
4. Bake cookies in a 325° oven until lightly browned, 15-20 minutes. Let cookies cool, then use a wide spatula to transfer to racks to cool completely.