Preheat oven to 350 degrees F. Grease an 9x9'' baking dish.
In a large bowl combine the flour, sugar, baking powder, salt, milk, egg and vanilla. Stir in melted butter. Pour mixture into prepared pan and smooth into an eve layer.
Make the cinnamon swirl topping by creaming all ingredients together until smooth.
Drop spoonfuls of the mixture evenly over the cake batter. Use a knife to swirl through the cake and disperse the mixture throughout the cake batter.
Bake 30-35 minutes or until a toothpick inserted in the center comes out clean. Drizzle frosting over warm cake. Serve warm.
For the Cream Cheese Frosting, cream the butter and cream cheese together. Add powdered sugar, vanilla, and enough milk to make a smooth, slightly thin frosting. Drizzle frosting over the cake with a spoon (or use a squirt bottle like I did--j