Open the cans of cinnamon roll dough and set the icing packets aside for later use. Cut each cinnamon roll into 6 pieces. In a small bowl, combine the granulated sugar and ground cinnamon. Mix well to create the sugar-cinnamon mixture.
In a separate bowl, toss the cut cinnamon roll pieces with the melted butter, ensuring that all the pieces are evenly coated. Roll the butter-coated cinnamon roll pieces in the sugar-cinnamon mixture, making sure they are fully coated.
Arrange the coated cinnamon roll pieces evenly in the greased baking dish or bundt pan. If there’s any leftover melted butter or sugar-cinnamon mixture, drizzle it over the pieces.
Bake for 30-35 minutes, or until the casserole is golden brown and cooked through (it takes longer to bake in the bundt pan). Use a toothpick to check for doneness; it should come out clean or with a few crumbs.