Mix flour, baking powder and salt in large bowl.
Beat butter and sugar in second bowl until creamy, 3 minutes. Beat in yolks and vanilla. On low speed, beat in flour in 3 batches, until dough forms. Divide dough in half and cover. Refrigerate 1 hour.
Heat oven to 350 degree F. Coat 2 large baking sheets with nonstick cooking spray.
On floured surface, roll half of dough to 1/8-inch thickness. With 2-inch heart-shaped cutter, cut out cookies. Place on prepared sheet(s). Gather scraps; re-roll; cut out for a total of 40 cookies. Refrigerate 20 minutes.
Bake at 350 degree F for 8 minutes; dont let brown. Let stand 1 minute. Remove to racks to cool.
Roll out remaining dough. With 2-inch heart-shaped cutter, cut out 40 cookies, re-rolling scraps. Using 1-inch heart-shaped cutter, cut out centers. Place cut- out and small cookies on separate sheets.
Bake at 350 degree F for 5 to 6 minutes for small cookies, 8 minutes for larger cookies. Cool as above.
Beat powdered egg whites, water and sugar on low speed 2 minutes to combine; increase to high and beat 4 minutes, until thickened and creamy. Tint half pink. Spread small hearts with pink or white icing. Use icing to attach candies to cut-out heart cookies as desired. Spread 1 teaspoon jam on each of the large solid heart cookies; top each with a cutout heart cookie. Makes 40 filled heart-shaped cookies and 40 small hearts.