Scalloped Potato Green Bean Casserole – Best Creamy Side

Scalloped Potato Green Bean Casserole is a hearty side dish that brings together two classic comfort foods in one pan. The creamy, cheesy sauce coats every slice of potato and every green bean, while a crispy topping adds texture. This dish is perfect for holiday dinners, potlucks, or a cozy Sunday meal.

What makes this casserole stand out is the balance of flavors and textures. The potatoes become tender and soak up the creamy sauce, while the green beans retain a slight crunch if you blanch them first. The golden, bubbly top is irresistible, and the whole dish comes together with simple ingredients you likely already have.

I've broken down the steps to ensure perfectly cooked potatoes every time. By layering the ingredients and baking at the right temperature, you'll get a casserole that's evenly cooked, not watery, and with a beautiful golden crust. Let's get started.

About the Ingredients

2 lbs (900g) russet potatoes, peeled and thinly sliced (1/8-inch thick)

Russets hold their shape and absorb sauce well. Substitute Yukon Golds for a buttery flavor; no need to peel if you prefer.

1 lb (450g) fresh green beans, trimmed and cut into 2-inch pieces

Fresh beans give the best texture. Frozen green beans work in a pinch; thaw and pat dry before using.

2 tbsp (28g) unsalted butter

For the roux and for greasing the dish. Use salted butter and reduce added salt if you prefer.

1 small yellow onion, finely chopped (about 1/2 cup)

Adds savory depth. Shallots or leeks are great substitutions.

2 cloves garlic, minced

Fresh garlic is best; use 1/2 tsp garlic powder if in a pinch.

3 tbsp (24g) all-purpose flour

Thickens the sauce. For gluten-free, use a 1:1 gluten-free flour blend.

2 cups (480ml) whole milk

Whole milk creates a richer sauce. Use 2% for lighter, but avoid skim to prevent curdling.

1 cup (240ml) low-sodium chicken or vegetable broth

Lowers salt and adds flavor. Low-sodium is key so the casserole isn't too salty.

1 tsp Dijon mustard

Adds subtle tang. Yellow mustard works too.

1/2 tsp salt

Adjust to taste. If using salted butter, reduce to 1/4 tsp.

1/4 tsp black pepper

Freshly ground preferred.

1 1/2 cups (170g) shredded sharp cheddar cheese, divided

Sharp cheddar gives bold flavor. Gruyere or Swiss are excellent substitutes.

1/2 cup (50g) panko breadcrumbs

For crispy topping. Regular breadcrumbs work, or crushed crackers for extra crunch.

Tips & Tricks

• Slice potatoes uniformly (1/8-inch) to ensure even cooking. Use a mandoline for best results.
• Blanch green beans for 2 minutes in boiling water, then shock in ice water to keep their vibrant color and crispness.
• Let the casserole rest 10 minutes after baking to set, making it easier to serve and preventing it from falling apart.

Step-by-Step Instructions

1. Preheat and Prep

Preheat oven to 375°F (190°C). Grease a 9×13-inch baking dish with butter or nonstick spray. Slice potatoes and blanch green beans: boil beans for 2 minutes, then transfer to ice water. Drain and set aside.

2. Make the Sauce

In a large saucepan, melt butter over medium heat. Add onion and cook until soft, about 3 minutes. Add garlic and cook for 30 seconds. Stir in flour and cook for 1 minute, stirring constantly. Slowly whisk in milk and broth. Bring to a simmer, stirring, until thickened, about 3-4 minutes. Remove from heat and stir in mustard, salt, pepper, and 1 cup of shredded cheese until melted.

3. Layer the Casserole

Spread a thin layer of sauce on the bottom of the dish. Arrange half of the potato slices in an even layer, slightly overlapping. Top with half of the green beans. Pour half of the remaining sauce over the top. Repeat with remaining potatoes, beans, and sauce.

4. Add Cheese and Topping

Sprinkle the remaining 1/2 cup of cheese over the casserole. In a small bowl, toss panko with a little melted butter or oil (optional) and sprinkle evenly over the top.

5. Bake Covered

Cover the dish with foil and bake at 375°F (190°C) for 30 minutes. This traps steam and helps potatoes cook through without burning the top.

6. Uncover and Finish

Remove foil and continue baking for 15-20 minutes, until the top is golden brown and the edges are bubbly. The potatoes should be tender when pierced with a fork.

7. Rest and Serve

Let the casserole rest for 10 minutes before serving. This allows the sauce to set and makes serving easier. Garnish with fresh parsley if desired.

Delicious Variations

• Add cooked, crumbled bacon or ham for a smoky, meaty twist.
• Swap the green beans for broccoli or asparagus for a different vegetable medley.
• Use a mix of cheeses like Gruyere and Parmesan for a nuttier, more complex flavor.

How to Store Scalloped Potato Green Bean Casserole

Frequently Asked Questions

I hope this Scalloped Potato Green Bean Casserole becomes a new favorite in your kitchen. Give it a try and let me know how it turns out in the comments below!

Scalloped Potato Green Bean Casserole

Scalloped Potato Green Bean Casserole is a creamy, comforting one-dish side that combines tender potatoes and crisp green beans in a golden, cheesy sauce.

★★★★½ 4.8 (156 ratings)

15 minPrep time50 minCook time8Servings285 kcalCalories

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🧂 Ingredients

• 2 lbs (900g) russet potatoes, peeled and thinly sliced (1/8-inch thick)
• 1 lb (450g) fresh green beans, trimmed and cut into 2-inch pieces
• 2 tbsp (28g) unsalted butter
• 1 small yellow onion, finely chopped (about 1/2 cup)
• 2 cloves garlic, minced
• 3 tbsp (24g) all-purpose flour
• 2 cups (480ml) whole milk
• 1 cup (240ml) low-sodium chicken or vegetable broth
• 1 tsp Dijon mustard
• 1/2 tsp salt
• 1/4 tsp black pepper
• 1 1/2 cups (170g) shredded sharp cheddar cheese, divided
• 1/2 cup (50g) panko breadcrumbs

📋 Instructions

1. 1Preheat and Prep — Preheat oven to 375°F (190°C). Grease a 9×13-inch baking dish with butter or nonstick spray. Slice potatoes and blanch green beans: boil beans for 2 minutes, then transfer to ice water. Drain and set aside.
2. 2Make the Sauce — In a large saucepan, melt butter over medium heat. Add onion and cook until soft, about 3 minutes. Add garlic and cook for 30 seconds. Stir in flour and cook for 1 minute, stirring constantly. Slowly whisk in milk and broth. Bring to a simmer, stirring, until thickened, about 3-4 minutes. Remove from heat and stir in mustard, salt, pepper, and 1 cup of shredded cheese until melted.
3. 3Layer the Casserole — Spread a thin layer of sauce on the bottom of the dish. Arrange half of the potato slices in an even layer, slightly overlapping. Top with half of the green beans. Pour half of the remaining sauce over the top. Repeat with remaining potatoes, beans, and sauce.
4. 4Add Cheese and Topping — Sprinkle the remaining 1/2 cup of cheese over the casserole. In a small bowl, toss panko with a little melted butter or oil (optional) and sprinkle evenly over the top.
5. 5Bake Covered — Cover the dish with foil and bake at 375°F (190°C) for 30 minutes. This traps steam and helps potatoes cook through without burning the top.
6. 6Uncover and Finish — Remove foil and continue baking for 15-20 minutes, until the top is golden brown and the edges are bubbly. The potatoes should be tender when pierced with a fork.
7. 7Rest and Serve — Let the casserole rest for 10 minutes before serving. This allows the sauce to set and makes serving easier. Garnish with fresh parsley if desired.

👨‍🍳 Chef's Note: For an extra crispy topping, broil the casserole for the last 2-3 minutes, watching closely to prevent burning.

Servings: 8

Cuisine: American

Course: Side Dish

Nutrition (per serving): 285 kcal · 12g protein · 22g carbs · 9g fat

Written by Diego Ramirez
Diego explores the intersection of technology and personal finance, sharing his journey of automating savings and investing spare change. He writes for beginners who want to make their money work harder without jargon.