Cream the butter and sugar. Add the eggs and mix well. Add the baking powder, baking soda, salt, yogurt and vanilla and mix well. Add flour and beat at low speed until blended. Spread in the pan. Put the blueberries on top.
In a small bowl, mix the topping ingredients together, then sprinkle over the berries. Bake 40-50 minutes, until done. Use a toothpick or knife to check the middle and make sure it's done.