Leftover Mac and Cheese Soup

Leftover Mac & Cheese Soup is a creamy, quick way to turn yesterday’s macaroni and cheese into an easy new dinner. Serve with a side of crusty bread, and dinner is done!

What to Make with Leftover Mac and Cheese

Got leftover mac and cheese? Bring your favorite mac back to life by serving it in a whole new way!

One of the best things about the day after Thanksgiving is all the leftovers, but let’s be honest; some hold up better than others. Holiday Stuffings and Green Bean Casseroles are all just as tasty the next day. 

Mac and cheese can be a different story. It’s just the nature of the dish. When left overnight in the fridge, pasta tends to soak up whatever sauce it is sitting in. This can leave the dish drier overall, and, well, it’s just not as good as it was that first day.

When faced with leftover mac and cheese, the best option is to repurpose it.

This soup takes about 20 minutes, and works with any style of mac – baked, stovetop, boxed, homemade, all of it.

Ingredients for Leftover Mac & Cheese Soup

Here’s what you’ll need. Exact amounts are listed in the printable recipe card at the bottom of the post.

• Butter – Used for sautéing the onions and garlic, adding richness to the soup.
• Yellow Onion and Garlic – Adds savory flavor and texture to the soup base.
• All-Purpose Flour – Used as a thickening agent to give the soup its creamy consistency.
• Chicken-style Broth – The base of the soup; Better Than Bouillon’s No-Chicken Base works well as a vegan option for chicken broth.
• Cheddar Cheese – Adds a tangy, cheesy flavor. I used mild cheddar, but sharp cheddar cheese also works well. For a different flavor profile, cheddar can be swapped for mozzarella, Gouda, or whatever suits the style of your mac. 
• Cream Cheese – For a rich and creamy texture to the cheesy soup.
• Milk – I use dairy-free oat milk because it has a mild flavor that I find similar to dairy-based whole milk.
• Prepared Mac and Cheese – You will need leftover macaroni and cheese ready to go for this soup. 

How to Make Leftover Mac & Cheese Soup

STEP ONE: Melt the Butter. Set a large pot over medium-high heat and add the butter. When the butter is melted, add the onions. Sauté onion for 2 minutes, until softened and fragrant.

STEP TWO: Add the Garlic. Add garlic and continue cooking for an additional 30 seconds.

STEP THREE: Add the Flour. Whisk in the flour until incorporated; the mixture will be thick.

STEP FOUR: Add the Broth. Gradually add the broth, whisking until the consistency is smooth.

STEP FIVE: Heat. Bring just to a boil, then reduce the heat to low.

STEP SIX: Add Cheeses and Milk. Add the cream cheese, cheddar cheese, milk, and black pepper to the pot. Stir frequently until the cheeses are melted.

STEP SEVEN: Stir in Mac and Cheese. Add the prepared mac and cheese, stirring to distribute throughout the soup.

STEP EIGHT: Season and Serve. Adjust seasoning to taste, and serve hot.

Storage and Reheating

• Let the soup cool, then store in an airtight container in the refrigerator. Reheat slowly over low or medium heat, stirring occasionally so the cheese melts smoothly again.

More Easy Soup Recipes 

• Leftover Mashed Potato Soup
• Cheese and Vegetable Chowder
• Cheesy Cauliflower Soup
• Broccoli Cheddar Soup

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Leftover Mac and Cheese Soup Recipe

Turn cold macaroni and cheese into a smooth, cheesy soup. A quick and comforting way to revive leftover mac and cheese!

5 from 12 votes

Print Pin Rate

Course: Dinner, Lunch

Cuisine: American

Keyword: comfort food, green chile mac and cheese, leftovers, soup, Thanksgiving, vegetarian

Prep Time: 10 minutes minutes

Cook Time: 10 minutes minutes

Total Time: 20 minutes minutes

Servings: 6

Calories: 795kcal

Author: Holly Gray

Cook ModePrevent your screen from going dark

Ingredients

• 1/4 cup butter
• 1/4 cup yellow onion finely chopped
• 2 teaspoons garlic minced
• 1/4 cup all-purpose flour
• 4 cups chicken-style broth
• 2 cups cheddar cheese shredded
• 4 ounces cream cheese
• 1/3 cup milk
• 1/4 teaspoon ground black pepper
• 4 cups mac & cheese prepared

Instructions

• Set a large pot over medium-high heat and add the butter. When the butter is melted, add the onions. Cook, stirring frequently for 2 minutes, until softened and fragrant.
• Add garlic and continue cooking for an additional 30 seconds.
• Whisk in the flour until incorporated; the mixture will be thick.
• Gradually add the broth, whisking until the consistency is smooth.
• Bring just to a boil, then reduce the heat to low.
• Add the cream cheese, cheddar cheese, milk, and black pepper to the pot. Stir frequently until cheeses are melted.
• Add the prepared mac and cheese, stirring to distribute throughout the soup.
• Adjust seasoning to taste and serve hot.

Nutrition

Calories: 795kcal | Carbohydrates: 93g | Protein: 24g | Fat: 37g | Saturated Fat: 6g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 2g | Trans Fat: 1g | Sodium: 2349mg | Potassium: 340mg | Fiber: 3g | Sugar: 3g | Vitamin A: 721IU | Vitamin C: 1mg | Calcium: 291mg | Iron: 4mg

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This post was updated on November 25, 2025, to add new information.