1. In a medium bowl, mix together the butter, sugar and almond extract until light and fluffy using an electric mixer.
2. Add beaten egg except for 1 teaspoon.
3. Sift flour and baking powder, and add to bowl, mixing with wet ingredients using a sturdy spoon until dough forms a ball.
4. Press dough into a greased 9 inch round cake pan or pie plate.
5. Mix the reserved 1 tsp of beaten egg with 1 tsp of water, and brush over dough.
6. Sprinkle with sliced almonds, if desired. (Oma always used the almonds, it looks pretty and adds a nice touch!).
7. Bake at 350°F for 25-30 minutes or until the top is light golden brown (firm to the touch).
8. This is a dense cake, but should be soft on the inside and hard on the outside, but not too hard!