Raspberry Lemon Thumbprints

Preheat oven to 350 degrees F. Line 2 large cookie sheets with parchment paper. In small bowl, stir jam and liqueur; set aside. In medium bowl, whisk flour, baking powder, and salt. In large bowl, with mixer on medium speed, beat butter and sugar until light and fluffy, about 3 minutes. Add yolks, lemon peel and juice, and vanilla; beat to combine. Gradually beat in flour mixture just until moist clumps form. Gather dough into ball in bowl. Pinch off and roll dough into 1-inch balls. Arrange 1 inch apart on cookie sheets; make indentation in center of each using floured index finger. Fill each with scant 1/2 teaspoon jam mixture. Bake 20 minutes or until golden. Cool completely on wire racks. Drizzle with melted white chocolate. Let set. (Refrigerate if necessary.) Store cookies in airtight container layered with waxed paper in freezer up to 1 month.