Crunchy Coffee Cake

Heat the oven to 400 degrees F. Lightly coat an 8-inch cake pan with butter and dust with all-purpose flour. Sift the cake flour, baking powder, salt, and cinnamon into a large mixing bowl. Beat in the butter one heaping 1/4 teaspoonful at a time, using an electric mixer set on low speed, until the mixture resembles coarse sand. Beat in the sugar a tablespoon at a time, until the mixture resembles fine damp sand. Beat in the eggs one at a time. Add the vanilla, lemon extract, and milk, beat on medium-high, just until blended. Do not over beat. Set aside 1/2 cup batter. Bake remaining batter in an 8-inch cake pan at 400 degrees F for 20 minutes. Make the topping: Cut the 4 tablespoons of butter with the granulated and light-brown sugars, the cake flour, and the cinnamon, and mix with reserved cake batter. Sprinkle over the baking cake and continue to bake until a skewer tests clean and the topping is bubbling — about 15 more minutes.