Move oven rack to bottom position and preheat oven to 375 degrees F (190 degrees C). Lightly grease 12 2-inch tart tins.
Roll out pastry and cut 12 3-inch circles. Fit one pastry circle into each tart tin. Spread one teaspoon of raspberry jam into the bottom of each tart shell.
In a medium mixing bowl, cream together softened butter or margarine and white sugar until light and fluffy. Mix in egg. Add flour, baking powder, and almond extract and mix until all ingredients are thoroughly combined. Pour 1 tablespoon of batter into each tart shell.
Bake in preheated oven for 20 minutes, until risen and firm. Dust tarts with confectioners' sugar.
