Cream butter and granulated sugar together until light and fluffy
½ cup butter, 1 cup granulated sugar
Add eggs and lemon zest and mix until well combined
2 eggs, 1 zest from one lemon
Add flour, baking powder, baking soda and salt. Mix just until the flour is partially combined. You should still see a lot of the flour not mixed all the way in.
1 ½ cups flour, 1 teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon salt
Mix in sour cream until sour cream is fully mixed in
1 cup sour cream
Place batter in a greased 8 inch square baking dish
Topping
Make topping by combining melted butter, brown sugar, 1 tablespoon of flour, walnuts and crushed corn flakes.
2 cups Corn Flakes, ½ cup brown sugar, ½ cup walnuts, 3 tablespoons melted butter, 1 tablespoon flour
Sprinkle topping over the cake batter
Bake in a preheated 350° oven for 30-35 minutes until baked through
Allow cake to cool before slicing and serving
Notes
Crush corn flakes by hand so you still have some remaining larger pieces. Just take a handful of the cereal and crush in the palm of your hand by making a fist.
Test cake by inserting a toothpick in the center of the cake. If the toothpick comes out clean, the cake is done. If wet crumbs still remain, bake for another 3-5 minutes.
Once sour cream is added to the batter, just mix until everything is combined. Don't overmix.
Store coffee cake covered at room temperature for 3-4 days. The topping may begin to lose its crunchiness the longer it sits.
Calories are estimated at one slice of cake when the cake is cut into nine pieces