Preheat the oven to 350F. Grease a 9x13-inch baking pan with non-stick cooking spray. Set aside.
In a large mixing bowl, stir together the dry ingredients (flour, baking powder, sugar, and salt).
In another bowl, whisk the eggs. Then, whisk in the milk, melted butter, and vanilla extract. Pour into the dry ingredients. Mix together using a spatula until combined. Transfer to the prepared pan. Set aside.
Make the topping: In a mixing bowl, beat together the softened butter, brown sugar, flour, and cinnamon using an electric mixer. Spoon the cinnamon topping over the cake batter. Swirl it using a knife.
Bake for 30-35 minutes or until ready. Check the readiness of the Cinnabon cake using a toothpick inserted in the center, if it comes out clean - the cake is ready.
Prepare the frosting. Mix together cream cheese, powdered sugar, milk, and vanilla extract. Add more milk to achieve the desired consistency. Pour over the warm cake. Then, slice and serve.