Preheat oven to 350 F. degrees. Grease a 8x8 inch square baking pan & set aside.
Stir together the butter & sugar in a large bowl. Add the egg, sour cream, yogurt & vanilla, and mix well.
Stir in the flour, baking powder, & baking soda together and mix until well combined.
Mix in apples.
Topping: In a small bowl stir the brown sugar, white sugar , butter and cinnamon together.
Pour batter into the greased baking pan (I use the back of a spoon to spread it out so it's all laying evenly). Using a spoon sprinkle the topping over the batter in the pan.
Bake at 350 F. for about 30 minutes or until a wooden toothpick comes out clean after being inserted into the center. Cool before serving.
Recipe by THE SEMISWEET SISTERS at https://www.thesemisweetsisters.com/2020/11/23/apple-cinnamon-coffee-cake/