Easy Baked Potato and Veggie Casserole for Busy Weeknights

A baked potato and veggie casserole is one of the easiest ways to turn simple pantry staples into a filling, comforting dinner. Thin potato slices bake in a creamy cheddar sauce with broccoli, carrots, peas, and sweet bell pepper, so every spoonful has tender potatoes and colorful vegetables. It is hearty enough to serve as a main dish and simple enough for a weeknight.

This casserole works well for family dinners, potlucks, or meal prep. It reheats nicely, and you can change the vegetables to match what you have in the fridge.

A finished casserole with golden cheese and colorful vegetables.

Table of Contents

Why You’ll Love This Recipe

Simple ingredients: Potatoes, vegetables, milk, cheese, and a few pantry seasonings are all you need.
One-dish meal: Potatoes and vegetables cook together, so you get a complete dinner in one baking dish.
Customizable: Swap in the vegetables you like best or add cooked ham or sausage if you want more protein.
Great texture: The sauce turns creamy and thick, while the top becomes lightly browned and bubbly.
Make-ahead friendly: You can assemble the casserole in advance and bake it later.

Ingredients

2 pounds (900 g) russet or Yukon Gold potatoes, about 4 medium, scrubbed
1 tablespoon (15 ml) olive oil
1 small yellow onion (about 1 cup, 120 g), diced
1 medium red bell pepper (about 1 cup, 150 g), diced
1 medium carrot (about 1/2 cup, 60 g), thinly sliced
2 cups (150 g) small broccoli florets
1 cup (150 g) frozen peas, thawed
2 cloves garlic, minced
3 tablespoons (45 g) unsalted butter
3 tablespoons (24 g) all-purpose flour
2 cups (480 ml) whole milk
1 1/2 cups (180 g) shredded sharp cheddar cheese, divided
1/2 teaspoon (3 g) salt, plus more to taste
1/2 teaspoon (1 g) black pepper
1/2 teaspoon (1 g) smoked or sweet paprika
2 tablespoons (10 g) chopped fresh chives or green onions, for garnish

Ingredient Notes

Potatoes: Russets become fluffy and absorb the sauce well. Yukon Golds hold their shape a little better and have a naturally buttery flavor. Either works here.

Vegetables: Broccoli, carrots, and peas add color and texture. Zucchini, mushrooms, or spinach are realistic substitutions. Add spinach at the end of the sauce step so it only wilts.

Milk and cheese: Whole milk gives the sauce a rich body. Two percent milk works, though the sauce will be a little thinner. Sharp cheddar adds plenty of flavor, and you can use a Monterey Jack and cheddar blend if you prefer a milder taste.

Flour and butter: Together they form a roux that thickens the sauce. This simple base keeps the casserole creamy without heavy cream.

Equipment You’ll Need

9 by 13 inch (23 by 33 cm) baking dish
Large skillet
Large pot for boiling potatoes
Sharp knife and cutting board
Whisk and wooden spoon
Aluminum foil

How to Make Easy Baked Potato and Veggie Casserole

Preheat the oven. Heat the oven to 400°F (200°C) and move a rack to the center. Lightly grease the baking dish with cooking spray or a little butter.
Prepare the potatoes. Peel the potatoes if you prefer, then slice them into rounds about 1/4 inch (6 mm) thick. Thin, even slices cook at the same rate.
Parboil the potatoes. Place the slices in a pot of salted water and bring to a simmer. Cook for about 5 minutes, until the edges are just tender when pierced with a fork but the centers still have some firmness. Drain well and set aside.
Sauté the vegetables. Heat the olive oil in a large skillet over medium heat. Add the onion, bell pepper, and carrot, and cook for 5 to 6 minutes, stirring occasionally, until softened and lightly golden at the edges.
Add the garlic and broccoli. Stir in the garlic and cook for about 30 seconds, until fragrant. Add the broccoli and cook for 2 minutes, just until bright green. Transfer the vegetables to a plate.
Make the roux. Melt the butter in the same skillet over medium-low heat. Sprinkle in the flour and whisk for about 1 minute. The mixture should look like a thick paste with no dry flour visible.
Build the sauce. Slowly pour in the milk while whisking constantly to prevent lumps. Simmer gently for 3 to 5 minutes, stirring often, until the sauce coats the back of a spoon.
Season and add cheese. Stir in the salt, black pepper, and paprika. Remove the pan from the heat and stir in 1 cup (120 g) of the cheddar until melted and smooth. Taste and adjust the salt.
Layer the casserole. Spread one-third of the potatoes in the baking dish and top with half the vegetables and peas. Pour over one-third of the sauce. Repeat with another layer of potatoes, the remaining vegetables, and half the remaining sauce. Finish with the last potatoes and the rest of the sauce, pressing the potatoes gently so the sauce reaches the bottom.
Bake covered. Cover the dish tightly with foil and bake for 20 minutes. This step steams the potatoes and helps them cook through.
Bake uncovered. Remove the foil, sprinkle the remaining 1/2 cup (60 g) of cheddar over the top, and bake for 15 to 20 minutes more. The casserole is done when the sauce bubbles around the edges, the cheese is golden, and a knife slides easily through the center potatoes.
Rest and serve. Let the casserole stand for 10 minutes so the sauce thickens and the slices hold their shape. Garnish with chives or green onions before serving.

Layering the potatoes and vegetables before adding the sauce.

The sauce should be smooth and thick enough to coat a spoon.

Pro Tips for the Best Results

Slice potatoes evenly. A mandoline or sharp knife helps you get uniform rounds, which bake more evenly.
Do not skip parboiling. Partly cooking the potatoes first prevents crunchy centers when the casserole comes out of the oven.
Cook the roux fully. Whisking the flour for a full minute removes the raw flour taste from the sauce.
Warm the milk slightly. Room-temperature or warm milk blends into the roux more smoothly than cold milk straight from the fridge.
Season the sauce before layering. Potatoes absorb salt, so a well-seasoned sauce makes the whole dish taste balanced.
Let it rest. Cutting the casserole too soon makes the slices fall apart and the sauce run.

Common Mistakes to Avoid

Using slices that are too thick. Thick potatoes can stay firm in the middle even after the top browns. Stick to about 1/4 inch slices.

Adding cold milk all at once. This can make the sauce lumpy. Pour the milk in slowly while whisking.

Overcrowding the vegetables. Too many vegetables can release water and thin the sauce. Cook them until just tender before layering.

Skipping the foil step. Baking uncovered from the start can dry the top before the potatoes are cooked through.

Variations and Substitutions

Ham or sausage: Add 1 cup (140 g) of diced cooked ham or browned breakfast sausage between the layers.
Vegetarian version: Use vegetable broth in place of any meat, and add sliced mushrooms with the onions.
Herb flavor: Stir 1 teaspoon of dried thyme into the sauce for an earthy taste.
Spicy version: Add 1/4 teaspoon of cayenne pepper or a diced jalapeño with the bell pepper.
Dairy-free option: Use unsweetened oat milk and a dairy-free shredded cheese. The texture will be slightly different.

Serving Suggestions

Serve the casserole with a crisp green salad dressed with lemon vinaigrette, which balances the richness of the cheese. Roasted chicken, baked fish, or a simple sliced ham also pair well. For a lighter meal, add a bowl of steamed green beans on the side.

Storage and Reheating

Refrigerator: Cool the casserole to room temperature for no more than 1 to 2 hours, then cover and refrigerate. It is best eaten within 3 to 4 days.

Freezer: Potato casseroles with dairy sauces can separate after freezing, so the texture may change. If you freeze it, wrap portions tightly and use within 2 to 3 months.

Reheating: Warm individual portions in the microwave in 30-second intervals, stirring between each. For a crisper top, reheat the casserole covered with foil in a 350°F (175°C) oven until hot throughout.

Frequently Asked Questions

Can I make this casserole ahead of time?

Yes. Assemble the casserole, cover it tightly, and refrigerate it for up to 24 hours. Add about 10 minutes to the covered baking time because the dish will be cold when it goes in the oven.

Why are my potatoes still hard in the middle?

The slices may have been too thick or the casserole was not covered long enough. Make sure the potatoes are about 1/4 inch thick and bake until a knife slides easily through the center.

Can I use frozen vegetables?

Yes. Thaw and drain frozen vegetables well before adding them. Excess water can make the sauce thin.

What cheese works best?

Sharp cheddar gives the most flavor. Monterey Jack, Colby, or a blend of cheeses also melt well.

How do I know when the casserole is done?

The sauce should bubble around the edges, the cheese should be golden, and a knife should slide through the potatoes with little resistance.

Can I make it without dairy?

You can try unsweetened oat milk and a dairy-free cheese. The sauce will be less rich and may not thicken the same way, so taste and adjust the seasoning.

Recipe Card

Recipe Name: Easy Baked Potato and Veggie Casserole

Short Description: A creamy, cheesy baked casserole with thin potato slices, broccoli, carrots, peas, and bell pepper.

Prep Time: 25 minutes

Cook Time: About 50 minutes

Total Time: About 1 hour 15 minutes

Servings: 6

Course: Dinner, Main Dish

Cuisine: American

Cooking Method: Parboiling, sautéing, and baking

Ingredients: 2 pounds (900 g) potatoes; 1 tablespoon (15 ml) olive oil; 1 small yellow onion, diced; 1 medium red bell pepper, diced; 1 medium carrot, thinly sliced; 2 cups (150 g) broccoli florets; 1 cup (150 g) frozen peas, thawed; 2 cloves garlic, minced; 3 tablespoons (45 g) butter; 3 tablespoons (24 g) all-purpose flour; 2 cups (480 ml) whole milk; 1 1/2 cups (180 g) shredded sharp cheddar, divided; 1/2 teaspoon (3 g) salt; 1/2 teaspoon (1 g) black pepper; 1/2 teaspoon (1 g) paprika; 2 tablespoons chopped chives or green onions.

Instructions: Preheat the oven to 400°F (200°C). Parboil the sliced potatoes for about 5 minutes, then drain. Sauté the onion, bell pepper, and carrot, then add garlic and broccoli. Make a roux with butter and flour, whisk in milk, and simmer until thick. Season and stir in 1 cup of cheese. Layer potatoes, vegetables, and sauce in a baking dish. Cover and bake 20 minutes, then uncover, add remaining cheese, and bake 15 to 20 minutes more until bubbly and golden. Rest 10 minutes before serving.

Notes: Thin, even potato slices are key. Frozen vegetables should be thawed and drained well.

Storage: Refrigerate covered for up to 3 to 4 days. Freezing is possible but the texture may change.

Nutrition: Nutrition information is an estimate and may vary depending on the ingredients and brands used.

Join the Conversation

What is your favorite veggie to add to a casserole? Share your go-to combination in the comments, and let us know if you try this version with a different mix of vegetables.