1. Preheat oven to 450°. Whisk together mascarpone cheese and next 3 ingredients in a medium bowl. Cover and chill.
2. Meanwhile, fit piecrust into a 9-inch tart pan with removable bottom; press into fluted edges. Fold any excess dough over outside of pan, and pinch to secure to pan. (This will keep piecrust from sliding down pan as it bakes.) Line crust with aluminum foil, and fill with pie weights or dried beans.
3. Bake at 450° for 8 minutes. Remove weights and foil, and bake 3 to 4 more minutes or until golden brown. Remove from oven to a wire rack, and cool completely (about 15 minutes). Gently tap excess crust from sides of pan, using a rolling pin.
4. Spoon mascarpone mixture into cooled tart shell, spreading to edges. Arrange kiwifruit around outer edge of tart; place raspberries in center.
5. Combine apricot jam and 1 Tbsp. water in a small microwave-safe glass dish. Microwave at HIGH 25 seconds. Stir until well blended. Pour apricot mixture through a fine wire-mesh strainer into a bowl; discard solids. Brush fruit in tart with apricot mixture. Serve immediately.
*Apple jelly may be substituted. Decrease water to 2 tsp. in Step 5 and do not strain jelly mixture after heating.
Cheesecake-Filled Fresh Fruit Tart: Substitute 2 cups ready-to-eat cheesecake filling for mascarpone cheese. Increase lemon juice to 2 tsp. Proceed with recipe as directed.