Leftover mac and cheese becomes crispy, golden fritters in the pan, stretching a few spoonfuls into a whole dinner. The pasta and cheese hold everything together with just an egg and flour; serve them warm with melted butter and a simple salad or green vegetable to round out the plate.

Serves 2. 15 minutes, 12 at the stove.

About 700 calories a serving, 19 g protein, 66 g carbohydrate, 40 g fat. From USDA figures for 100% of the ingredients; amounts are the recipe's.

You need about 1 cup [240 g] mac and cheese, 1 egg, 3 tablespoons [25 g] flour, to taste salt, to taste pepper, 2 tablespoons oil, 2 tablespoons butter.

1. Crack one egg into a bowl with the mac and cheese and stir in three tablespoons flour and a pinch each of salt and pepper until the mixture holds together.
2. Heat two tablespoons oil in a large skillet over medium-high heat until shimmering. Form the mac and cheese into four or six flat cakes and slide them into the pan, pressing gently with the back of a spatula as they cook until the first side is golden, about three minutes.3 min
3. Flip the fritters carefully and cook the second side until golden, about two minutes more, while you warm two tablespoons butter in a small pan.2 min

Note Serve the fritters with the warm butter drizzled over top and a side salad or steamed vegetables. Leftovers keep in an airtight container for three days and can be reheated in a warm skillet. If you have fresh herbs like chives or parsley, chop them into the melted butter for serving.

Leftover mac and cheese transforms into something new when baked with ham and peas, held together by a light cream sauce and cheese. This is the weeknight answer to half a container taking up space in the fridge.

Serves 2. 25 minutes, 10 at the stove.

About 210 calories a serving, 13 g protein, 15 g carbohydrate, 11 g fat. From USDA figures for 71% of the ingredients; amounts are the recipe's.

You need half container mac and cheese, 1 tablespoon butter, 1 tablespoon flour, 1/4 teaspoon salt, 1/4 teaspoon pepper, 4 ounces diced ham, 1/2 cup frozen peas.

1. Heat your oven to 350°F [175°C]. Melt 1 tablespoon butter in a small saucepan over medium heat, then whisk in 1 tablespoon flour and cook for one minute, stirring constantly, until it smells toasted.
2. Pour in 3/4 cup milk slowly, whisking to break up lumps. Cook for two minutes, stirring often, until the sauce thickens enough to coat the back of a spoon, then season with 1/4 teaspoon salt and 1/4 teaspoon pepper.2 min
3. Fold the half container of mac and cheese into the cream sauce along with 4 ounces of diced ham and 1/2 cup frozen peas until everything is coated. Transfer to a baking dish.
4. Bake for 12 to 15 minutes until the top is golden and the edges bubble around the pan. Let it rest for two minutes before serving.14 min

Note Swap the ham for cooked sausage or skip it entirely for a vegetarian version. Leftovers keep in the fridge for three days and reheat gently on the stovetop. Serve with a simple green salad or steamed broccoli on the side to stretch the meal.

Turn leftover mac and cheese into something hot and crispy by binding it with an egg, panfrying it into cakes, and finishing them in a hot oven. You'll have dinner for two in twenty minutes and a reason to make mac and cheese again tomorrow.

Serves 2. 25 minutes, 20 at the stove.

About 520 calories a serving, 16 g protein, 60 g carbohydrate, 24 g fat. From USDA figures for 80% of the ingredients; amounts are the recipe's.

You need 1 serving (about 1 cup) mac and cheese, 1 egg, 2 tablespoons oil, to taste salt, to taste pepper, 1/4 cup panko breadcrumbs, as much as you like green salad or tomato.

1. Crack 1 egg into a bowl, beat it, then fold in 1 cup leftover mac and cheese and 1/4 cup panko breadcrumbs with a pinch of salt and pepper until combined.
2. Set a medium skillet over medium-high heat with 2 tablespoons oil until it shimmers. Gently press half the mixture into a rough cake shape and slide it into the pan, then do the same with the rest of the mixture, leaving space between them.
3. Let them cook without moving until the bottoms are golden and crisp, about four minutes, then flip each one carefully and cook the other side until it browns, another two to three minutes. While they cook, heat your oven to 400°F [200°C].6 min
4. Transfer the cakes to a baking sheet and slide them into the oven until the tops crisp up and warm through, about five minutes, then serve right away with salad or fresh tomato on the side.5 min

Note Swap breadcrumbs for crushed crackers or crushed chips if you have them. Leftovers keep in the fridge for three days and reheat well in a toaster oven. Serve with a sharp green salad or sliced tomato with salt and vinegar.