Yogourt Coffee Cake

Tuesdays are garbage days, which means the fridge (hopefully) gets cleaned out and I discover forgotten treasures. I had an entire container of unopened plain yogourt reaching its due date. So I made four coffee cakes... and gave three away. It's easy karma. This tasty version is based on a Joy of Cooking coffee cake:

Cake
2 C all-purpose flour
1 tsp baking powder
1 tsp baking soda
1/2 tsp salt
1 1/4 C plain yogourt
1 tsp vanilla extract
1 C sugar
1/4 C butter
2 eggs

Streusal
1/4 C butter
3/4 C flour
1 C granulated sugar
1 C demerrara sugar

1. Grease one 11x13 inch pan, or 2 11 inch round cake pans. Do not flour.
2. Sift the flour, baking powder baking soda and salt together.
3. In another bowl, mix the vanilla into the yogourt.
4. In a third bowl, cream the 1/4 C butter and 1 C sugar together until light and fluffy.
5. Add the eggs and mix well.
6. Alternate adding the flour and yogourt, mixing well after each addition.
7. Dump into prepared pan(s).
8. Sprinkle with streudal.
9. Cook at 350F fo 25-30 mins.