Green bean casserole is a beloved Thanksgiving side dish It has a crispy fried onion topping and a creamy mushroom sauce coating tender green beans Getting the right cooking time and temperature is key to achieving the ideal texture and flavor. So how long should you cook green bean casserole at 375 degrees Fahrenheit?
As a food blogger and home cook, I’ve made this classic casserole many times Through trial and error, I’ve landed on 25-30 minutes as the ideal baking time for green bean casserole at 375°F. This gives you a finished dish with tender beans, a bubbling sauce, and crispy fried onions.
Below I’ll walk through why 375°F is the right temperature and explain exactly how long you should bake green bean casserole to perfection. I’ll also share some extra tips for nailing this Thanksgiving staple. Let’s dive in!
Why 375 Degrees is the Best Temperature for Green Bean Casserole
Most green bean casserole recipes call for baking at 375°F, and there’s good reason for that. Here’s why 375° is ideal:
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It’s hot enough to boil the liquid and bubble the sauce while cooking the green beans through. Lower temperatures may not activate the starch and thicken the sauce properly.
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It crisps up the fried onion topping. Higher heat would burn the onions before the inside is cooked through.
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It’s high enough to evaporate excess moisture for concentrated flavors but not so high that the sauce breaks or gets dried out.
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It’s a common oven temperature. Most home ovens and recipes use 325, 350, 375 or 400°F. 375°F hits the sweet spot for this dish.
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It matches the temperature for cooking other Thanksgiving foods. Stuffing, casseroles and more are often baked at 375°F.
Some recipes suggest broiling the casserole briefly at the end to crisp the onions more. But I find 375°F is sufficient to achieve a nice crunch without having to broil and risk burning.
How Long to Bake Green Bean Casserole at 375°F
Baking time can vary a bit depending on the exact recipe, amount of liquid, oven variances and more. But in general, you should bake green bean casserole at 375°F for 25-30 minutes.
Here’s a timeline of what happens during that optimal cooking time:
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15 minutes: The sauce starts bubbling around the edges and thickening. Beans soften slightly.
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20 minutes: Sauce is actively boiling and has thickened throughout. Beans are cooked through but still have bite.
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25 minutes: Beans are very tender but not mushy. Sauce is thick and coats beans evenly. Onions have started crisping.
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30 minutes: Beans are fully tender. Sauce has reduced down and intensified in flavor. Onions are nicely crisped and golden brown.
I recommend checking at 25 minutes and then continuing to bake until the sauce reaches your desired consistency and the onions are as crispy as you like.
It’s better to slightly underbake and then return to the oven for a few more minutes if needed. Overbaking can lead to dry, mushy beans and a broken sauce. Use the visual cues above as a guide.
Handy Tips for Perfect Green Bean Casserole
Beyond the right time and temperature, there are some other useful tips to ensure green bean casserole success:
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Use fresh green beans. For tender beans with vibrant color, buy fresh green beans. Frozen works in a pinch too. Avoid canned beans which can be mushy.
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Undercook the green beans slightly before assembling. Par-cook fresh beans in boiling water for 2-4 minutes first. This preps them so they finish cooking through when baked.
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Pat the beans dry before mixing. Drying the beans helps the sauce coat evenly and prevents excess moisture.
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Toast the onions first. Crisp up the fried onions in the oven for 5 minutes before topping to maximize crunch.
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Sprinkle some onions between layers. This adds onion flavor throughout and prevents a soggy top layer.
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Let the casserole rest before serving. Sitting for 5-10 minutes after baking helps the sauce thicken up perfectly.
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Store leftovers properly. To maintain the crisp onions, store casserole and onions separately. Re-crisp the onions in the oven before reheating the whole dish.
Signs Your Green Bean Casserole is Over or Undercooked
Knowing what to look for when the timer goes off can confirm if your casserole is ready or needs a little more time. Here’s what to check:
Overcooked signs:
- Dry, shrunken beans
- Broken sauce that’s separated from the beans
- Burnt fried onions
Undercooked signs:
- Crunchy, raw tasting beans
- Thin, watery sauce
- Soft, mushy onions
Perfectly cooked:
- Tender beans with a hint of bite
- Thick, creamy sauce coating each bean
- Crispy, golden brown fried onions
Get it just right, and you’ll have a green bean casserole the whole family will love!
The Best Recipe for Classic Green Bean Casserole
Now that you know how long to bake it and the right temp to use, here’s my go-to recipe for classic green bean casserole.
Ingredients:
- 1 pound fresh green beans, trimmed
- 1 can condensed cream of mushroom soup
- 1/2 cup milk
- 1 tsp soy sauce (optional)
- Freshly ground black pepper
- 1 1/3 cups French’s crispy fried onions
Instructions:
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Preheat oven to 375°F. Lightly grease a 2-quart baking dish.
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Cook green beans in boiling salted water for 3-4 minutes until just tender. Drain and rinse under cold water. Pat very dry with paper towels.
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In a large bowl, stir together the condensed soup, milk and soy sauce if using until smooth. Season with pepper to taste.
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Add green beans and toss to coat. Transfer mixture to prepared baking dish.
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Bake for 25-30 minutes until bubbling and beans are tender. Remove from oven.
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Top with crispy fried onions, reserving some to sprinkle just before serving. Bake 5 minutes more.
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Let sit for 5-10 minutes before serving. Sprinkle remaining onions on top.
For a tasty twist, stir in cooked bacon pieces or sautéed mushrooms. Serve this Thanksgiving favorite hot alongside all the turkeys and fixings!
Get Creative with Unique Green Bean Casserole Ideas
Once you master the classic, there are plenty of ways to put your own creative spin on green bean casserole:
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Substitute browned butter or roasted garlic cream soup for condensed mushroom soup
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Use cashew cream for a dairy-free sauce
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Add crispy fried shallots instead of onions
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Mix in roasted chestnuts, dried cranberries, or bread crumbs
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Top with crushed potato chips, Parmesan, or sourdough crumbs
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Make it vegetarian by using vegetable broth and omitting the soy sauce
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Swap in asparagus, Brussels sprouts or broccoli for green beans
The possibilities are endless! Use your favorite flavors and ingredients while keeping the same baking time and temp.
Common Green Bean Casserole FAQs
Here are answers to some frequently asked questions about cooking this holiday staple:
How long does it last in the fridge?
Leftover assembled casserole will keep 4-5 days refrigerated. Store onions separately to retain crispiness.
Can you freeze it?
Yes! Assemble casserole as directed but don’t add topping. Freeze unbaked casserole up to 2-3 months. Thaw in fridge before baking.
Can it be made ahead?
Absolutely! Assemble up to 1 day ahead but don’t bake until ready to serve. Refrigerate until baking.
Can I use frozen green beans?
Frozen, not canned! Thaw first and pat dry. Add a couple minutes to the cooking time.
Do I have to use condensed soup?
No, you can make your own white sauce. But traditional condensed soup works great.
Do I need to boil the green beans first?
Parboiling for 2-4 minutes helps them cook evenly but isn’t mandatory. Just increase baking time.
Enjoy This Favorite Thanksgiving Casserole
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