Prep the bundt pan. Preheat the oven to 350° F/ 176° C. Once completely cooled, grease the walls of the bundt pan with butter. Set the pan into a dutch oven or baking dish.
Bake the flancocho. Add hot water to the baking dish the bundt pan is sitting in. Cover loosely with aluminum foil and carefully transfer to the oven. Bake for 60-90 minutes, or until a toothpick comes out clean from the cake.
Cool, flip & serve. Let the flancocho rest in the water bath for 20 minutes before removing from the water bath and setting aside to cool (this can take up to 2 hours). Carefully loosen the sides of the cake with a knife.