Preheat oven to 375 degrees F. Grease and flour an 8-inch square pan and set aside.
Topping: In small bowl, combine topping ingredients. Blend with fork until crumbly. Set aside.
Cake: Sift 1 1/2 cups sifted flour with baking powder and salt into a bowl. In a medium bowl, beat together beaten egg and 1/3 cup melted butter. Add milk and vanilla. Stir in flour mixture. Pour batter in greased pan.
Sprinkle crumb mixture evenly on top. Bake for 25-30 minutes. Allow to cool before serving.
by The Savvy Kitchen