Many of the recipes that I loved while working at West Branch Pond Camps have been altered for the better by my father. His general rule is to "add more of the good stuff" and I can't argue with his track record. This coffeecake recipe is a Chuck-improved version of the Everyday Coffee Cake + Streusel Layer from the 1963 McCall's Cookbook.
1 1/2 cups Flour, sifted
2 1/2 teaspoons Baking Powder
1 teaspoon Cinnamon
1/2 teaspoon Salt
3/4 cup Sugar
1/3 cup (75 g) Butter, soft
1/2 cup (4 oz) Milk
1 1/2 teaspoon Vanilla
1 cup Dark Brown Sugar, packed
4 tablespoons (57 g) Butter, soft
4 tablespoons Flour
2 teaspoon Cinnamon
Preheat oven to 375 F (190 C)
Grease a 9"x 9" pan (2x recipe for a 9" x 13" pan)
Make the streusel by combining the 1 cup Brown Sugar, 4 tablespoons softened Butter, 4 tablespoons Flour, and 2 teaspoons Cinnamon. Set bowl aside.
In a separate bowl, sift the 1 1/2 cups Flour, 2 1/2 teaspoons Baking Powder, 1 teaspoon Cinnamon, and 1/2 teaspoon Salt. Set aside.
In a stand mixer, beat the 1 egg until frothy, and then add in the 3/4 cup Sugar and 1/3 cup (75 g) Butter, and cream until well combined.
Add in the 1/2 cup (4 oz) Milk, 1 1/2 teaspoon Vanilla and mix on medium-low until combined.
Add in the flour mixture a little at a time, and mix on low until combined.
Pour half the cake batter in the greased pan.
Add half of the streusel layer evenly.
Pour in the remaining cake batter and then top with the streusel. With a butter knife, gently "swirl" the streusel so that it is (lightly) incorporated into all of the cake batter, not just the top and middle. Don't worry if the middle layer of streusel is not fully covered by the remaining cake batter, but do try to make the cake batter as flat as possible.
Bake at 375 F (190 C) for 25-30 min or until a toothpick or knife comes out clean.