Apple Coffee Cake

Preheat oven

Preheat oven to 350°F (175°C).

Prepare baking dish

Spray an 8-inch square baking dish with cooking spray; dust with 1 tablespoon flour.

Cream butter and sugar

Beat 1/4 cup butter and 3/4 cup brown sugar together with an electric mixer in a large bowl until light and fluffy. The mixture should be noticeably lighter in color.

Add egg

Beat egg into butter mixture.

Add wet ingredients

Add sour cream, vanilla yogurt, and vanilla extract to the mixture; beat to integrate.

Combine dry ingredients

Stir 1 cup flour, 3/4 teaspoon cinnamon, baking soda, and salt together in a bowl; add to the butter mixture and beat to combine into a batter.

Fold in apples

Fold apples into the batter.

Pour into pan

Pour batter into prepared baking dish.

Make streusel topping

Mix 1/4 cup brown sugar, 1/4 cup flour, 2 tablespoons butter, and 1/2 teaspoon cinnamon together in a bowl using a fork to achieve a crumbly consistency; sprinkle over the top of the batter.

Bake

Bake in the preheated oven until a toothpick inserted into the center comes out clean, 35 to 40 minutes.

Cool

Cool in the pan for 10 minutes before removing to cool completely on a wire rack.