Preheat oven to 350 degrees. Grease and flour a 12 cup bundt pan.
In a large bowl, add cake mix, apple cider, ½ cup melted butter, 4 eggs, and 2 teaspoons cinnamon. Beat together until fully combined.
Pour into the prepared bundt pan. Bake for 35 to 40 minutes or until a toothpick inserted in the center comes out clean.
Let cool in the pan for 20 minutes. Remove from pan to cooling rack to cool.
Line a serving plate with parchment paper and place cooled cake on top.
In a small bowl, mix together sugar and 1 teaspoon cinnamon.
Brush the top and sides of the cake with 3 tablespoons melted butter.
Coat the cake with half of the cinnamon sugar mixture, pressing it into the sides.
Let the cake stand for 15-20 minutes and then cover with the remaining cinnamon sugar mixture.
Slice and serve!