Why You’ll Love This Recipe

It tastes fresher and more vibrant than the classic version with canned soup.
You control every ingredient — less sodium, better texture, more flavor.
The homemade creamy sauce and crispy onion topping bring layers of texture and richness.
It’s versatile — you can make parts ahead, adapt to what you have, or adjust it for vegetarians.
Impress your guests with something classic but made “from scratch.”

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

For the crispy onion strings

1 medium onion, thinly sliced into rings or strings
Buttermilk (or milk + a splash of lemon juice or vinegar)
All-purpose flour
Seasonings: salt, pepper, onion powder (optional), smoked paprika (optional)
Oil for frying

For the creamy green bean casserole

Fresh green beans, trimmed and cut (or blanched)
Unsalted butter
Onion (diced)
Mushrooms (sliced)
Garlic, minced
All-purpose flour (for thickening)
Chicken or vegetable broth
Half-and-half (or a mix of milk + cream)
Salt and pepper
Optional seasonings (thyme, red pepper flakes, nutmeg, etc.)

Directions

Make the crispy onion strings
- Soak the sliced onion in buttermilk (or milk + acid) for a little while to mellow the bite.
- Meanwhile, combine flour and seasonings in a shallow bowl or dish.
- Remove onion slices from the milk, dredge in flour mixture, then fry in hot oil (in batches) until golden and crisp. Drain on paper towels. Set aside.
Blanch the green beans
- Bring a pot of salted water to boil.
- Add the green beans and cook just until they turn bright green and become crisp-tender (a few minutes).
- Immediately plunge them into ice water to stop cooking. Drain well.
Prepare the creamy sauce & vegetables
- In a skillet or saucepan over medium heat, melt butter. Add diced onion and cook until softened.
- Add sliced mushrooms, season with salt and pepper, and sauté until they release moisture and begin to brown.
- Stir in garlic, cooking briefly until fragrant.
- Sprinkle the flour over the veggies and stir to coat; cook a minute or two to remove raw flour taste.
- Gradually pour in broth, stirring constantly, and let it thicken a bit.
- Lower heat, then stir in the half-and-half (or milk/cream mixture). Simmer until the sauce is creamy and thick enough to coat beans. Adjust seasoning.
Combine and bake
- Gently fold in the blanched green beans so they’re coated in the sauce.
- Transfer to a greased casserole dish if your skillet isn’t ovenproof.
- Top with most of the crispy onion strings (reserve some for garnish).
- Bake in a preheated oven until bubbly around the edges and the onion topping is lightly browned (about 15 minutes or so).
- Remove from oven, sprinkle the remaining onion strings on top, and let rest a few minutes before serving.

Servings and timing

Servings: about 8
Prep time: ~30 minutes (includes prepping onions, green beans, sauce)
Cook time / bake time: ~25 minutes
Total time: ~55–60 minutes

Variations

Use mushroom-only or omit mushrooms entirely if you don’t like them.
Swap half-and-half for heavy cream for a richer sauce, or use whole milk (though sauce will be lighter).
Add herbs like thyme, rosemary, or a pinch of nutmeg for extra depth.
Use vegetable broth instead of chicken broth for a vegetarian version.
Mix in other vegetables like peas, asparagus tips, or steamed carrots.
For the topping, use panko breadcrumbs or crushed crackers instead of fried onions for a different crunch.
Prepare the onion strings ahead of time, or use store-bought crispy onions in a pinch (stir some in and top with more).

Storage/Reheating

Store leftover casserole (without extra onion topping) in an airtight container in the refrigerator for up to 3–4 days.
Reheat in the oven (or in a skillet) until warmed through and bubbly; you can sprinkle fresh crispy onions on top just before serving to restore crunch.
Avoid reheating in the microwave if you want to maintain texture, especially of the cream sauce and topping.

FAQs

Can I substitute frozen or canned green beans?

Yes — you can use frozen (thawed and drained) or canned (drained) beans. But fresh beans give the best texture and flavor.

Do I have to make the onion strings from scratch?

No — you can use store-bought crispy fried onions. Just stir some into the sauce and reserve some for topping.

Can I assemble this ahead of time?

Yes — you can prepare the sauce and beans ahead, even assemble in the dish, but wait to bake until you’re ready to serve to keep textures better.

What can I use instead of half-and-half?

You can use a mix of milk + cream or use whole milk (though sauce will be lighter). Using all heavy cream will make it richer.

How can I thicken the sauce if it’s too thin?

Mix a little extra flour (or cornstarch) with cold liquid (broth or milk) and stir it into the sauce while simmering until it thickens.

Can I make this vegetarian?

Yes — just use vegetable broth instead of chicken broth and skip any non-vegetarian additions.

Will the topping stay crispy after baking?

It may lose some crispiness during baking. To preserve crunch, reserve some onion strings to add just before serving.

Can I double the recipe?

Yes — just double all ingredients, and use a larger casserole dish. You may need a bit more bake time to get it bubbly.

How do I prevent the sauce from getting watery?

Ensure beans are well drained after blanching, avoid excess liquid, and don’t overbake. Also, get the sauce thick before combining.

Conclusion

This from-scratch creamy green bean casserole elevates a holiday classic. You get fresh green beans, a flavorful mushroom-onion cream sauce, and that craveable crunch from crispy onions — all made with love and control over ingredients. It’s perfect for special dinners or holiday feasts, and one of those comforting sides you’ll want to serve again and again.

Creamy Green Bean Casserole from Scratch

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Creamy Green Bean Casserole from Scratch is a comforting, homemade take on the classic holiday side dish. Made with fresh green beans, sautéed mushrooms, a rich creamy sauce, and crispy fried onions — no canned soup required. It’s flavorful, fresh, and made entirely from real ingredients.

Author: Laura
Prep Time: 30 minutes
Cook Time: 25 minutes
Total Time: 55–60 minutes
Yield: 8 servings
Category: Side Dish
Method: Baking
Cuisine: American
Diet: Vegetarian

Instructions

Make crispy onion strings: Soak sliced onions in buttermilk for about 10–15 minutes. In a bowl, combine flour and seasonings. Dredge onions in flour mixture and fry in hot oil until golden brown. Drain on paper towels and set aside.
Blanch green beans: Boil salted water, add green beans, and cook until bright green and crisp-tender (about 3–4 minutes). Transfer to ice water to stop cooking, then drain well.
Prepare creamy sauce: In a skillet, melt butter over medium heat. Add diced onion and sauté until soft. Add mushrooms, season, and cook until they release liquid and brown. Stir in garlic and cook briefly.
Sprinkle flour over the vegetables, stir, and cook for 1–2 minutes. Gradually whisk in broth, letting it thicken. Reduce heat and add half-and-half. Simmer until creamy, adjusting seasoning with salt, pepper, and herbs.
Combine and bake: Fold in the blanched green beans until coated. Transfer mixture to a greased casserole dish. Top with most of the crispy onions (reserve some for garnish).
Bake at 375°F (190°C) for 15–20 minutes, until bubbly and lightly browned. Top with remaining onions before serving.

Notes

For a vegetarian version, use vegetable broth instead of chicken broth.
Make onion strings ahead or use store-bought crispy onions for convenience.
Ensure green beans are well-drained to prevent a watery sauce.
Reserve some crispy onions to add right before serving for maximum crunch.

Nutrition

Serving Size: 1 cup
Calories: 210
Sugar: 5g
Sodium: 280mg
Fat: 13g
Saturated Fat: 6g
Unsaturated Fat: 6g
Trans Fat: 0g
Carbohydrates: 18g
Fiber: 3g
Protein: 6g
Cholesterol: 25mg