Preparation Combine almonds and 1/2 cup sugar in processor and process until almonds are finely chopped. Mix flour, powdered sugar, baking powder and salt in medium bowl. Using electric mixer, beat butter, egg yolk and almond mixture in large bowl to blend. Beat in vanilla and almond extracts. Mix dry ingredients into butter mixture in 3 additions. Cover dough and refrigerate until firm, about 1 hour. Preheat oven to 350°F. With hands, roll 1 generous tablespoonful of dough for each cookie into 1 1/4-inch-diameter ball. Place cookies on 2 ungreased baking sheets, spacing 2 inches apart. Make depression in center of each cookie with fingertip or handle of wooden spoon. Bake cookies 10 minutes. Press back of teaspoon into cookies to re-form depressions. Fill each depression with 1/2 teaspoon preserves. Continue baking cookies until light golden brown around edges and on bottom, about 8 minutes longer. Cool on baking sheets 2 minutes. Using metal spatula, transfer cookies to rack and cool completely. (Can be made 3 days ahead. Store between sheets of waxed paper in airtight container at room temperature.)
Preparation Combine almonds and 1/2 cup sugar in processor and process until almonds are finely chopped. Mix flour, powdered sugar, baking powder and salt in medium bowl. Using electric mixer, beat butter, egg yolk and almond mixture in large bowl to blend. Beat in vanilla and almond extracts. Mix dry ingredients into butter mixture in 3 additions. Cover dough and refrigerate until firm, about 1 hour. Preheat oven to 350°F. With hands, roll 1 generous tablespoonful of dough for each cookie into 1 1/4-inch-diameter ball. Place cookies on 2 ungreased baking sheets, spacing 2 inches apart. Make depression in center of each cookie with fingertip or handle of wooden spoon. Bake cookies 10 minutes. Press back of teaspoon into cookies to re-form depressions. Fill each depression with 1/2 teaspoon preserves. Continue baking cookies until light golden brown around edges and on bottom, about 8 minutes longer. Cool on baking sheets 2 minutes. Using metal spatula, transfer cookies to rack and cool completely. (Can be made 3 days ahead. Store between sheets of waxed paper in airtight container at room temperature.)