Slow Cooker Cinnamon Breakfast Cake

In a small bowl, mix the cinnamon and sugar for the cinnamon sugar. Set aside. In a large bowl, whisk together the flour, baking powder, salt, baking soda, and sugar. Add the milk, eggs, vanilla, and oil; until incorporated. Spread about half the batter into generously greased slow cooker. Sprinkle with the cinnamon sugar mixture. Top with remaining batter, and use a knife to gently swirl cinnamon sugar through batter. Cook on high for about 1-1/2 hours until center of cake is set. Cake is done when a wooden skewer inserted in the center comes out clean. Serve warm with butter and maple syrup. This can stand alone as a simple breakfast, or serve smaller portions along with other breakfast favorites like eggs, hash browns, and bacon.