Preheat the oven to 350 degrees Fahrenheit. Spray a 10 inch bundt pan with non-stick cooking spray. Be sure to get in all the cracks and crevices.
In a large mixing bowl, stir together the powdered cake mix with the apple cider, apple sauce, eggs, cinnamon, brown sugar, and vanilla extract.
Pour the batter into the prepared bundt pan. Bake in your preheated oven for 45-50 minutes, or until an inserted skewer comes out clean.
Cool in the pan for 20 minutes before flipping it out to a cooling rack.
In a small mixing bowl, combine the cinnamon and granulated sugar together.
Use a pastry brush to brush the melted butter over the entire cake.
Before the butter sets, sprinkle the cinnamon sugar mixture over the entire cake. You want it to stick to the butter.
Let the cake stand for 10 minutes to set and dry. Slice and serve slightly warm or at room temperature.