Lemon Hearts (Zitronenherzen)

Beat egg yolks, 2/3 cup sugar and the vanilla in medium-size bowl until thick and lemon-colored. Stir in half the almonds, the lemon extract and baking powder. Transfer dough to well-sugared surface; knead in enough of the remaining almonds to form soft dough. Shape into a ball. Refrigerate wrapped in plastic wrap until cold, about 1 1/2 hours.

Heat oven to 400°F. Line baking sheets with greased waxed paper. Roll dough on lightly sugared surface 1/4 inch thick. Cut out cookies with 2 inch heart-shaped cutter. Place on baking sheets. Bake until edges are golden, 8 to 10 minutes.

Make lemon icing. Spread on warm cookies. Cool on wire racks.