Place the seam side down in the prepared dish. In a medium saucepan, over medium heat, combine butter, white sugar, brown sugar, and water. Bring to boil, stirring constantly. Once boiling, reduce heat and simmer for 3 minutes. Pour sauce over enchiladas and let stand 45 minutes. Preheat the oven to 350 degrees F. Bake in the preheated oven 20 minutes or until golden.