For the pastry cream, in a medium saucepan combine sugar and flour; gradually stir in milk. Add egg yolks, beating until smooth. Cook and stir over medium heat until thickened and bubbly, stirring often. Remove from heat. Stir liqueur or vanilla into pastry cream; pour into a bowl and cover surface with plastic wrap. Cool, then chill.

For tart shells, thaw pastry according to package directions. Unfold pastry sheets, one at a time, on a lightly floured surface. Roll lightly to minimize ridges. Using 2 1/2- to 3-inch cookie cutters, cut out about 24 tarts (be sure to cut out an even number of each shape); place half of them on an ungreased baking sheet and prick each a few times with a fork. Using 1-1/2- to 2-inch cutters (of the same design or round), cut the middle out of the remaining pastries, reserving cutouts.

Brush edges of the tarts on baking sheet with water and top with tarts that have the middles cut out; press gently to fuse layers together to form taller tart shells. Arrange small cutouts on another ungreased baking sheet. Bake pastries in a 400 degree F oven until puffed and golden, allowing 7 to 9 minutes for small cutouts and 10 to 12 minutes for larger tarts. Cool pastries completely.

Up to 1 hour before serving time, add mascarpone cheese to chilled pastry cream; beat with an electric mixer on low speed until smooth. Carefully spoon mixture into tart shells. Melt semisweet chocolate and shortening together in a small saucepan over very low heat, stirring constantly. Remove from heat. Spread a thin layer of chocolate over tops of small cutouts. Pipe or drizzle remaining chocolate over the cream-filled tarts; refrigerate both until chocolate is set.

To serve, arrange filled tarts and chocolate-glazed cutouts on large platter and surround with berries. Makes 12 servings.

Prepare pastry cream, cool, cover, and chill up to 4 hours before adding the cheese.