These delicious grilled cheese sandwiches with caramelized onions are easy to make, especially if you make the caramelized onions ahead of time. Make a batch and keep in the fridge for 3 to 4 days. You can add them to everything from meatloaf to scrambled eggs. We like to add sliced garlic to the onions during the last 5 minutes of cooking time for another layer of flavor. There's nothing better or more satisfying, or simpler to make than a grilled cheese sandwich or any hot sandwich. These recipes can be changed any way you'd like. Use a different bread, a different cheese, more cheeses, or add veggies such as sliced tomatoes, sauted bell peppers, or spinach or other greens. You could also add some sauted apples or pears for a sandwich reminiscent of fall. Add some crisply cooked bacon or thinly sliced ham for a fabulous variation. If you change the recipe, write down the changes so you can reproduce your masterpiece. These easy sandwiches can be served with nothing but a cold glass of milk, but you could add a green salad or a fruit salad for a complete meal.