1. Grease pan. Preheat oven to 350 F (180 C).
2. Cream butter, sugar and vanilla sugar. Add eggs, one at a time, beat until light in color.
3. Mix flour, salt and baking powder. Add half of flour, beat until just blended. Add 3 tbs milk, just blend. Add rest of flour, just blend.
4. Batter should drop slowly from a spoon, forming long tips. If too firm add another tbs milk.
5. Spread batter evenly in pan.
6. Bake in lower third of oven 18-22 minutes until golden yellow. Let cool in form for 10 minutes, then remove and let cool completely on a wire rack.
7. Use immediately or store tightly wrapped for 24 hours or freeze.