Heat oven to 350°F In large bowl, combine flour, 1/2 cup powdered sugar and cornstarch; blend well. Add margarine and vanilla. By hand, blend until a soft dough forms. Shape dough into 1-inch balls. Place 1 ball in each of 36 ungreased miniature muffin cups; press in bottom and up sides of each cup.*.
Spoon 1 teaspoon pineapple preserves into each dough lined cup. In small bowl, combine sugar and egg. Using fork, beat until well blended. Stir in coconut until well coated with egg mixture. Spoon 1 teaspoon coconut mixture over pineapple preserves in each cup.
Bake at 350°F for 23 to 33 minutes or until crusts are very light golden brown. Cool 20 minutes. To release cookies from cups, hold muffin pan upside down at an angle over wire rack. Using handle of table knife, firmly tap bottom of each cup until cookie releases. Cool completely. Just before serving, sprinkle with powdered sugar. Yield: 3 dozen cookies.
TIP* If only 1 miniature muffin pan is available, keep remaining cookie dough refrigerated until ready to bake.