From Better Homes and Gardens December 2009. "The rich, gooey filling in these tarts has a hit of raspberry liqueur. Substitute your favorite liqueur or flavored syrup, or leave it out altogether.
1. Prepare Chocolate Pastry. Heat oven to 375°F Divide pastry in 24 balls. Evenly press each ball on bottom and sides or 24 ungreased 1 3/4-inch muffin cups, using floured fingers if necessary; set aside.
2. For filling, in small saucepan heat and stir chocolate and butter over medium-low heat until melted and smooth. Remove from heat. Stir in egg, sugar, liqueur, and vanilla. Spoon 1 scant tablespoon filling in each pastry shell.
3.Bake 12 to 15 minutes or until pastry is firm and filling is puffed. Cool in pans 10 minutes. Run sharp thin-blade knife around tassie edges; carefully remove from pans. Cool on wire rack. Pipe or dollop on a small amount of Chocolate Buttercream.
4. To store, refrigerate tassies in single layer in airtight container up to 3 days.
In food processor combine 1 1/4 cups all-purpose flour, 1/2 cup sugar, 1/4 cup natural unsweetened cocoa powder, and dash of salt; pulse to combine. Add 1/2 cup cold butter, cut up. Cover; process until crumbly. In small bowl whisk together 1 egg yolk and 2 tablespoons cold water. Add to processor; pulse until a dough ball forms (add water if dry). If needed, cover and refrigerate until easy to handle.
In a medium mixing bowl beat 1/4 cup softened butter on medium-high for 30 seconds. Gradually beat in 1 cup powdered sugar and 3 tablespoons unsweetened cocoa powder. Beat in 2 tablespoons milk. Gradually beat in 1 cup powdered sugar until piping consistency.