This cheesy, creamy macaroni and ham casserole is the perfect comfort food. It's also a great way to use up that leftover holiday ham. Add extra veggies to the macaroni mixture for extra color, texture, and flavor peas, broccoli, carrots, corn, or mixed vegetables are all good choices. If you don't have pimientos, omit or use roasted red bell peppers instead, or add chopped red bell pepper to the green bell pepper for a burst of color. Saut some mushrooms along with the onions and bell pepper. For a heartier one-dish meal, add extra ham and top it with more cheese, like swiss or cheddar jack. Add breadcrumbs toppings for extra crunch, and serve the casserole with a basic tossed salad or steamed vegetables, and biscuits or dinner rolls.