Adapted from Allrecipes.com
2 cups all-purpose flour
3/4 cup white sugar
2 teaspoons cinnamon
2 teaspoons baking powder
1/2 teaspoon salt
1/2 cup butter, softened
1/4 cup of milk
1/2 cup of sour cream
1 1/2 teaspoons vanilla extract
1 1/2 cup all-purpose flour- I'm not exactly sure on this, I generally just add flour to the butter and cinnamon mixture until crumbs form.
1 1/3 cup brown sugar
1 tablespoon ground cinnamon
1/2 cup butter
1.Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 8x8 inch pan.
Make the streusel topping: In a medium bowl, melt partially butter in microwave. Add brown sugar, cinnamon, and flour. If mixture is more of a paste than crumbles, add flour (a little at a time), until a crumb texture is reached. I generally use my hands when it gets closer to crumbs, I find it works best that way.
2. In a medium bowl, combine flour, salt, baking powder, and cinnamon, set aside. In a large bowl stir egg, milk, vanilla extract, and milk. Add dry ingredients to wet ingredients, stir until just combined, and fold in sour cream.Pour half the batter into prepared pan, sprinkle half of the streusel mix over batter, pour the rest of the batter into the pan and top with the remaining streusel.
3.Bake in the preheated oven for 25 to 30 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool.
I apologize in advance if my directions aren't clear enough. The ones on the original recipe were rather bizarre.