Preheat oven to 350 degrees F (175 degrees C). Grease and flour an 8 inch square pan.
In a medium bowl, mix together 1 cup flour, baking powder, baking soda and salt. In a large bowl, cream together the white sugar and 1/2 cup butter. Beat in the egg, then stir in the vanilla. Gradually beat in the dry ingredients alternately with the milk. Spread the batter into the prepared pan.
In a medium bowl, mix together the apples, brown sugar, 1/4 cup flour and 1/4 cup butter. Sprinkle over the batter. Bake in preheated oven for 30 to 40 minutes, or until a toothpick inserted in the center comes out clean.
Interesting Facts
The streusel topping consists of a combination of white and brown sugar, butter and flour, which is mixed together to form a crumbly texture.
This coffee cake is perfect for breakfast, brunch, or even as an afternoon snack.
Serve it warm, with a dollop of whipped cream or a scoop of ice cream for a real treat!