These slightly sweet onions are a flavorful topping for pizzas and pastas or as a sandwich condiment. To achieve a melt-in-your-mouth quality, the onions need to be cooked very slowly.
Heat butter in a large skillet over medium heat. Add onions, and sprinkle with sugar. Cook, stirring frequently, until soft and golden brown, about 1 hour, reducing heat to medium-low about halfway through. If onions begin to stick to skillet, add 1 to 2 tablespoons water. Remove from heat, and season with salt and pepper. Let cool before using.