1 cup of milk (whole is best in my opinion, but you certainly can use skim or 2%)
3 eggs
For the Swirl
1/4 cup sugar
1 TBSP cinnamon
(this can be doubled if you really like cinnamon)
For the Crumb Top
1/2 cup all purpose flour
3/4 cup sugar
1 TBSP cinnamon
8 TBSP (1 stick) of butter softened
Instructions
Cake Batter
Preheat oven to 350*. Grease and flour a 10″ spring form pan.
In a large mixing bowl cream together the 1 1/2 stick butter, 1 1/2 cups sugar, and 2 tsp vanilla extract.
In a separate bowl sift together 3 cups of flour and 4 TBSP baking powder. Add this to the butter sugar mixture. Set aside the empty bowl.
Add the cup of milk and three eggs. Mix all of this together until well combined. (You may get small lumps of butter in the batter if your butter wasn’t creamed well. This will be ok.) Set aside cake batter.
Swirl
In the bowl set aside earlier mix together the 1/4 cup sugar and 1 TBSP of cinnamon.
In the spring form pan, beginning with the cake batter, alternate layers of cake batter and the cinnamon swirl mixture. Sprinkle the cinnamon swirl mixture liberally. Two layers of the cinnamon mixture work well. (The cake batter is fairly thick and will need a spatula to spread. The layers do not need to be flat except for the final batter layer.) Set aside while you prepare the crumb top.
Crumb Top
Add 1/2 cup flour, 3/4 sugar, and 1TBSP cinnamon to the bowl that had contained the cinnamon swirl mixture. Use a fork and mix well.
Cut the 8 TBSP of butter into the flour, sugar, cinnamon mixture. Use the fork to mix until a medium sized pebbly mixture is formed.
Add the crumb mixture to the top of the cake batter in the spring form pan. Press slightly so that he mixture adheres to the batter.
Bake
Bake at 350* for 45-50 min. A fork will come away clean and the crumb topping will be browned.
Allow to cool well before removing from the spring form.
Notes
Grease well. Also, you may want to run a knife along the edge of the pan before opening the spring form pan. This cake has a tendency to stick.