Melt 2 tablespoons bacon grease in a 12-inch cast iron skillet over medium heat. Add eggs and scramble until not quite set. Remove to a plate.Add another 1-2 tablespoons bacon grease to the now-empty pan and add onion. Cook until tender. Add mushrooms and peppers and cook until tender. Remove all to a plate.Cook breakfast sausage until no longer pink. Remove to a plate.Add remaining 2 tablespoons bacon grease to the pan. Once it's hot, add cold rice. Cook, stirring often, until rice is hot and begins to brown. Add all of the cooked ingredients back to the pan, stir, and cook until hot.Serve immediately with fried eggs, butter, ketchup, and possibly a drizzle of maple syrup.