Beat butter and cream cheese at medium speed with an electric mixer until creamy; add flour, beating until blended. Cover and chill 1 hour.
Shape pastry into 24 (1-inch) balls. Place balls in ungreased miniature (1 3/4-inch) muffin pans; press evenly into bottom and up sides.
Spoon 1/2 teaspoon preserves into each tart. Stir together egg, sugar, and almond paste; spoon 1 teaspoon mixture over preserves, and sprinkle with chopped almonds.
Bake at 325° for 25 to 30 minutes. Cool slightly in pans on a wire rack; remove from pans, and cool completely. Freeze up to 1 month, if desired.