Jelly Centers

In large bowl, with mixer at low speed, beat margarine or butter with 1 cup sugar until blended, occasionally scraping bowl with rubber spatula. Increase speed to high; beat until light and fluffy, about 3 minutes. At low speed, beat in egg yolks and vanilla until blended. Gradually beat in flour, baking powder, and salt. Shape dough into 2 balls; flatten each slightly. Wrap each ball in plastic wrap and refrigerate 1 hour or until firm enough to roll. Preheat oven to 350 deg. Between 2 sheets of floured waxed paper, roll half of dough 1/8 inch thick, keeping remaining dough refrigerated. With floured 2-inch cookie cutter cut out as many cookies as possible. Place cookies, about 1/2 inch apart, on ungreased large cookie sheet; reserve trimmings. With 1/2-inch round or star-shaped cookie cutter, cut out centers from half of cookies. Remove centers; add to trimmings. In cup, with fork, beat egg whites slightly. With pastry brush, brush cookies with cutout centers with some egg white, then sprinkle with some of remaining 1/4 cup sugar. Bake all cookies 10 to 12 minutes, until cookies are lightly browned. With pancake turner, remove cookies to wire rack to cool. Repeat steps 2 and 3 with trimmings and remaining dough to make more cookies. When cookies are cool, spread center of each cookie without cutout center with 1/4 to 1/2 teaspoon jam; top each with a cookie with a cutout center, gently pressing cookies together to form a sandwich.