Preheat oven to 375°.
Prepare a 9-inch cake pan
In large bowl, cream butter and sugar
Mix in egg and milk
In separate bowl, sift flour, salt, and baking powder
Combine with wet ingredients
Stir until well mixed
Pour half of the batter into bottom of cake pan
Place half of the topping mixture over top
Pour remaining batter over top
Place remaining half of topping over the top
Bake approximately 35 minutes