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Cheesy Ham and Mashed Potato

Category: Dinner Ideas That Actually Work

This comforting dish combines creamy mashed potatoes blended with sharp Cheddar cheese and crispy fried onions. It’s shaped into a shell that holds a savory filling of diced ham, tender peas and carrots, and a creamy mushroom base seasoned with mustard, garlic, and pepper. Baked until golden and bubbly, the casserole finishes with an extra layer of melted cheese and crunchy onions on top for texture. It rests briefly before serving to enhance the melded flavors. Perfect for using leftovers or customizing with similar ingredients for a warm, hearty meal that’s both flavorful and satisfying.

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Lili Clark smiling at the camera.
Created By Lili Clark
Updated on Thu, 23 Apr 2026 15:48:24 GMT
A cheesy leftover ham and mashed potato casserole. Save
A cheesy leftover ham and mashed potato casserole. | lilicooks.com

This hearty cheesy leftover ham and mashed potato casserole transforms simple leftovers into a comforting, crowd-pleasing meal. Its rich layers of creamy mashed potatoes, savory ham, melting cheese, and colorful vegetables make it irresistible and perfect for easy weeknight dinners or cozy family gatherings.

Ingredients

  • Leftover mashed potatoes: brings creaminess and acts as the comforting base. Use smooth, well-seasoned potatoes for best texture
  • Shredded Cheddar cheese: divided between the layers provides rich flavor and gooey melting goodness. Sharp cheese offers a nice tang while mild is mellow
  • French fried onions: add a delightful crunch and bursts of savory flavor. Opt for fresh packages to ensure crispness
  • Diced leftover cooked ham: offers smoky, salty heartiness. Choose good quality ham with even marbling for tender bites
  • Frozen peas and carrots: add color and mild sweetness. Thaw and drain to avoid excess moisture in the casserole
  • Condensed cream of mushroom soup: binds the filling together and adds savory depth. Stir well before mixing for a creamy consistency
  • Dry mustard: infuses a subtle tangy kick that enhances all the flavors without overpowering
  • Granulated garlic: contributes gentle warmth and aroma. Fresh ground pepper adds a slight bite and rounds the seasoning

Step-by-Step Instructions

Sculpt the Potato Shell:
Mix half of the shredded Cheddar cheese and half the French fried onions into the mashed potatoes until evenly combined. Press the potato mixture firmly over the bottom and sides of a 2-quart casserole dish forming a thick shell. This creates a crispy potato crust that holds the filling.
Prepare the Filling:
In a large bowl combine the diced ham, thawed and drained peas and carrots, cream of mushroom soup, dry mustard, granulated garlic, and black pepper. Stir thoroughly until all ingredients are fully incorporated for a flavorful, cohesive filling.
Assemble and Cover:
Spoon the ham mixture gently into the prepared mashed potato shell, filling it evenly. Cover the casserole loosely with aluminum foil to prevent the top from drying out while baking.
Bake Covered:
Place the covered casserole into the preheated oven at 375 degrees Fahrenheit. Bake for 45 minutes allowing the filling to heat through and meld the flavors while the potato shell crisps underneath.
Add Toppings and Finish Baking:
Remove the casserole from the oven and sprinkle the remaining shredded Cheddar cheese and French fried onions evenly over the top. Return to the oven uncovered and bake for an additional 5 minutes until the cheese melts and the onions turn golden and crispy.
Rest Before Serving:
Remove the casserole from the oven and let it rest at room temperature for 5 to 10 minutes. This resting period helps the filling set slightly making it easier to cut and serve while enhancing the overall flavor.
A casserole with peas, carrots, and ham.
A casserole with peas, carrots, and ham. | lilicooks.com

Storage Tips

Store any leftovers in an airtight container in the refrigerator for up to three days. Reheat in the oven rather than microwave to retain the crispy top and avoid sogginess. This casserole also freezes well in individual portions so you can thaw and enjoy it on busy days.

Ingredient Substitutions

Swap leftover chicken or turkey for ham to change up the protein without altering the comforting nature. Use cream of chicken or cream of celery soup instead of mushroom for a different flavor profile. Frozen mixed vegetables like corn and green beans can be used in place of peas and carrots depending on your preference.

Serving Suggestions

Serve this casserole alongside a fresh green salad or roasted vegetables for a complete balanced meal. It pairs well with mustard or tangy ketchup on the side for those who like an extra flavor kick. Perfect for potlucks and family dinners because it’s easy to portion and satisfies a crowd.

Recipe FAQs

→ Can I substitute the ham with other meats?

Yes, diced cooked chicken or turkey work well as alternatives, lending a different but complementary flavor profile.

→ What cheese varieties work best for this dish?

Sharp or mild Cheddar both add great taste and melt nicely; feel free to experiment with other melting cheeses like Monterey Jack.

→ How do the fried onions contribute to the casserole?

They add a delightful crunchy texture and a savory, oniony flavor contrast to the creamy interior layers.

→ Is there a way to make this dish ahead of time?

Yes, you can assemble it in advance, keep it refrigerated, and bake it fresh when ready to enjoy for optimal texture.

→ Can I use fresh vegetables instead of frozen peas and carrots?

Absolutely, fresh peas and diced carrots can be used; just lightly steam or blanch them beforehand to soften.

→ What is the role of mustard and garlic powder in the filling?

They add a subtle depth and slight tang that brighten and enhance the overall savory flavors.

Cheesy Ham Mashed Potato

Creamy mashed potatoes, ham, and melted cheese baked with crispy onions and peas for a cozy meal.

Preparation Time
15 min
Cooking Time
50 min
Overall Time
65 min
Created By: Lili Clark

Category: Dinner

Skill Level: Beginner-Friendly

Cuisine Type: American

Output: 6 Serves (6 servings)

Dietary Options: ~

Ingredients

→ Base

01 3 cups leftover mashed potatoes

→ Cheese and Toppings

02 1 cup shredded Cheddar cheese, divided
03 1 (2.8 oz) package French fried onions, divided

→ Protein and Vegetables

04 1½ cups diced leftover cooked ham
05 1 (10 oz) package frozen peas and carrots, thawed and drained

→ Sauce and Seasonings

06 1 (10.75 oz) can condensed cream of mushroom soup
07 ¾ teaspoon dry mustard
08 ½ teaspoon granulated garlic
09 ¼ teaspoon freshly ground black pepper

→ Other

10 aluminum foil

Steps

Step 01

Heat the oven to 375°F (190°C).

Step 02

Combine half of the Cheddar cheese and half of the French fried onions with the mashed potatoes. Press the mixture evenly onto the bottom and up the sides of a 2-quart casserole dish to create a shell.

Step 03

In a separate bowl, mix the diced ham, thawed peas and carrots, cream of mushroom soup, dry mustard, granulated garlic, and black pepper until well combined.

Step 04

Spoon the ham and vegetable mixture into the mashed potato shell. Cover the dish loosely with aluminum foil.

Step 05

Bake in the preheated oven for 45 minutes.

Step 06

Remove the foil, sprinkle the remaining Cheddar cheese and French fried onions over the top, and bake uncovered for an additional 5 minutes until the cheese is melted.

Step 07

Remove from the oven and allow the casserole to rest for 5 to 10 minutes before serving.

Tips

  1. Use mild or sharp Cheddar cheese according to taste preference.

Required Tools

  • 2-quart casserole dish
  • Mixing bowls
  • Aluminum foil

Allergy Information

Always check each ingredient for allergens, and consult a medical professional if unsure.
  • Contains dairy and gluten ingredients

Nutritional Information (per serving)

These details are shared for general guidance and don’t replace professional advice.
  • Calories: 401
  • Fats: 23 g
  • Carbohydrates: 33 g
  • Proteins: 16 g