Ham and Vegetable Casserole: A Cozy One-Dish Dinner

Ham and vegetable casserole combines savory cooked ham, tender potatoes, carrots, broccoli, and cheddar in a creamy sauce, all baked together until bubbling. It is a flexible, filling one-dish dinner that makes good use of leftover ham, and the vegetables can be adjusted to suit what you have on hand.

Ingredients

2 tablespoons (28 g) unsalted butter, plus a little for greasing the baking dish
1 small yellow onion, about 1 cup (150 g), finely chopped
2 tablespoons (16 g) all-purpose flour
1 cup (240 ml) low-sodium chicken broth
1 cup (240 ml) whole milk
1 teaspoon Dijon mustard (5 ml)
½ teaspoon dried thyme (about 1 g)
¼ teaspoon black pepper (about 0.5 g), plus more to taste
½ teaspoon kosher salt (about 2 g), or less if the ham is salty
1 pound (450 g) Yukon Gold or other waxy potatoes, cut into ½-inch (1.3 cm) cubes
1 cup (120 g) carrots, peeled and cut into thin half-moons
2 cups (300 g) cooked ham, cut into ½-inch (1.3 cm) cubes
2 cups (180 g) broccoli florets, cut into bite-size pieces; fresh or frozen
1½ cups (170 g) shredded sharp cheddar cheese, divided
2 tablespoons (15 g) plain breadcrumbs, optional

Instructions

Heat the oven to 375°F (190°C). Lightly butter a 9-by-13-inch (23-by-33 cm) baking dish. Chop the onion, potatoes, carrots, and ham, keeping the potato cubes small and similar in size so they cook evenly. If using frozen broccoli, keep it frozen until needed; thawing it first can make the casserole watery.
Make the sauce. Melt the 2 tablespoons of butter in a medium saucepan over medium heat. Add the onion and cook for 4 to 5 minutes, stirring occasionally, until softened but not browned. Sprinkle in the flour and stir continuously for about 1 minute to cook away its raw taste. Slowly whisk in the broth and milk, a little at a time, so the sauce stays smooth. Stir in the mustard, thyme, salt, and pepper. Bring the sauce to a gentle simmer and cook for 2 to 3 minutes, whisking, until it lightly coats a spoon. It will thicken further in the oven.
Put the potatoes, carrots, and ham in the prepared dish and spread them into an even layer. Pour the warm sauce over the ingredients and gently stir so the pieces are coated. Cover the dish tightly with foil. A snug cover traps steam, which helps the potatoes cook through before the top browns.
Bake covered for 40 minutes. Carefully remove the foil, watching for escaping steam, and check a potato cube with a fork. The potatoes may still be firm at this stage; that is expected. If the sauce looks unusually thick or the edges appear dry, stir in 2 to 3 tablespoons (30 to 45 ml) of broth or milk before covering again.
Scatter the broccoli over the casserole and gently fold it into the hot mixture without crushing the potatoes. Sprinkle 1 cup (115 g) of the cheddar over the top. Cover and bake for 10 minutes, then uncover and bake for 15 minutes more, until the sauce bubbles around the edges, the broccoli is tender, and the cheese is golden in spots. For food safety, check the center with a food thermometer: USDA FSIS guidance for reheated leftovers is 165°F (74°C). If the center has not reached that temperature, cover and continue baking, checking again after a few minutes.
Let the casserole stand for 10 minutes before serving. This short rest lets the sauce settle, so portions are easier to lift from the dish. If using breadcrumbs, sprinkle them over the remaining ½ cup (55 g) of cheddar during the final 15 minutes of baking for a lightly crisp top.

Tips

Cut the potatoes into small, even cubes. Larger pieces can remain firm while the sauce is already bubbling, and uneven pieces cook at different rates. If you prefer larger potato chunks, parboil them in simmering water for about 6 to 8 minutes, drain well, and reduce the covered baking time by roughly 10 minutes; check that the vegetables are tender before serving.

Choose ham with its salt level in mind. Smoked or cured ham can be quite salty, so start with the smaller amount of salt in the ingredient list and taste the sauce before it goes into the baking dish. Low-sodium broth gives you more control. The sauce should taste gently seasoned on its own because the ham and cheddar add more savory flavor.

For frozen broccoli, add it straight from the freezer as directed. Excess surface ice can add liquid, so shake off loose ice crystals first. Avoid over-stirring once the broccoli is in the dish; gentle folding keeps the florets intact and prevents the potatoes from breaking down into the sauce.

If you need a gluten-free version, replace the all-purpose flour with a measure-for-measure gluten-free flour blend and use gluten-free breadcrumbs or leave them out. Check the broth and ham labels as well, since ingredients and processing vary. The sauce may thicken a little differently, so simmer it until it lightly coats a spoon rather than relying only on a precise minute count.

Serving Suggestions

This casserole is substantial enough to serve as the main course. A crisp green salad with a simple vinaigrette balances the creamy sauce, while steamed green beans or sautéed cabbage make an easy vegetable side if you want a fuller table. For a lighter contrast, serve sliced cucumber, radishes, or a plate of raw vegetables alongside it.

Bring the baking dish to the table while it is still warm, and spoon portions onto plates rather than cutting it into neat squares; the creamy sauce makes the portions tender. If serving bread, choose something crusty for scooping up the sauce. Because ham and cheese provide plenty of savory flavor, a side dish with lemon, vinegar, or fresh herbs is a useful counterpoint.

Variations

Swap the broccoli for 1½ to 2 cups (about 200 to 250 g) of peas, green beans, or cauliflower florets. Add peas during the last 10 minutes so they heat through without becoming soft. Green beans or small cauliflower florets can be added at the same time as the broccoli, though thicker pieces may need a few extra minutes. If using canned vegetables, drain them very well and stir them in only for the final 10 minutes; they are already cooked and can turn mushy with a longer bake.

For a different flavor, replace half the cheddar with Swiss cheese, which pairs well with ham and gives the sauce a milder, nuttier taste. A small pinch of smoked paprika can bring out the smoky notes in the ham, while a teaspoon of chopped fresh parsley stirred in after baking adds freshness. Keep add-ins modest so the sauce still coats the potatoes and vegetables.

You can also use sweet potato in place of some or all of the regular potato. Cut it to the same small size, but begin checking for tenderness a little earlier because it may soften faster. For a richer top, use extra cheddar; for more crunch, add the optional breadcrumbs. These changes are flexible, but the casserole should remain moist rather than packed tightly with extra ingredients.

Storage and Reheating

Refrigerate leftovers within 2 hours of cooking in a shallow, covered container. They keep for 3 to 4 days in the refrigerator. For easier reheating, divide the casserole into individual portions once it has cooled enough to handle; do not leave it out to cool for an extended period.

Reheat an individual portion in the microwave, covered loosely, stirring once if practical, until steaming hot throughout. For a larger amount, cover the dish with foil and warm it in a 350°F (175°C) oven until hot in the center. Use a food thermometer and bring reheated leftovers to 165°F (74°C), as recommended by USDA FSIS. Add a splash of milk or broth if the sauce has thickened in the refrigerator. You can freeze portions in airtight, freezer-safe containers for up to 2 months for best quality. Thaw overnight in the refrigerator before reheating; the potatoes may be a little softer after freezing.

Frequently Asked Questions

Can I make ham and vegetable casserole ahead?
Yes. You can prepare the sauce and chop the ham and vegetables up to a day ahead, then refrigerate them separately in covered containers. Assemble and bake the casserole when you are ready. If you assemble it completely in advance, the raw potatoes can discolor and release moisture, and a cold dish may need extra baking time. Use a thermometer to confirm the center reaches 165°F (74°C).

Can I use leftover holiday ham?
Yes. Cut cooked leftover ham into small cubes and use it in place of the cooked ham listed. Keep it refrigerated until you assemble the dish, and make sure the casserole heats to 165°F (74°C) in the center. If the ham is strongly seasoned or glazed, reduce the added salt and taste the sauce before baking.

Why are my potatoes still hard?
They may be cut too large, the foil may not have sealed tightly, or the oven may be running cool. Continue baking the covered casserole until a fork slides into a potato cube easily, checking every 5 to 10 minutes. If the sauce is becoming very thick, stir in a small splash of broth or milk and reseal the foil to keep steam inside.

Can I use other vegetables or frozen mixed vegetables?
Yes. Peas, green beans, cauliflower, and corn all work, but add delicate or already-cooked vegetables near the end so they do not become mushy. For a frozen mixed-vegetable blend, use about 2 cups (300 g), shake off any loose ice, and stir it in during the last 10 to 15 minutes of baking. The vegetables may release a little extra moisture, so let the casserole rest before serving.

How do I know when the casserole is done?
The sauce should bubble, the potatoes should be fork-tender, and the center should reach 165°F (74°C) on a food thermometer. Check the middle of the dish rather than only the browned edges, which heat faster. If the top is browned before the center is hot, cover it with foil and continue baking until the center reaches the safe temperature.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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