There's nothing quite like fresh green bean casserole made from scratch with fresh green beans and mushroom cream sauce! This recipe adds in caramelized onions for a decadent spin on this comfort food classic.
I've probably had green bean casserole more than any other casserole because it's just that popular in my Midwestern family. My take on this comfort food classic is a fresh green bean casserole that uses not only fresh par-boiled green beans, but fresh mushrooms and a creamy sauce made from scratch.
I promise that making this casserole from scratch is so worth the extra active time. Your Thanksgiving guests will definitely notice the difference between fresh and canned green bean casserole!
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Why this recipe works
- Par-boiled green beans: Fresh green beans are par-boiled before adding them to the green bean casserole. This results in tender, vivid green beans instead of mushy green beans.
- Double the onion flavor: Sure, you can make this recipe quicker and leave out the caramelized onions, but they add so much to this casserole! I have a secret tip for making quick caramelized onions (hint: baking soda!). They add a sweet and decadent twist in addition to classic French fried onions.
- Prep ahead: This casserole is perfect for Thanksgiving because it can be made in advance. The caramelized onions can also be made in advance.
- Homemade mushroom sauce: Instead of canned mushroom soup we're making a very easy but high-impact sauce with whole milk, garlic, salt, and pepper.
Ingredients
- Green beans: Fresh green beans are the centerpiece of this recipe but frozen can also be used.
- Fresh mushroom sauce: This is made with butter, chopped cremini mushrooms (white mushrooms also work), garlic, whole milk, all-purpose flour for thickening, and vegetable broth. I highly recommend Better than Bouillon vegetable base for the most flavorful vegetable broth.
- Caramelized onions: These add a lot of extra flavor and sweetness to this casserole. I use yellow onions but white onions will also work.
- Fried onions: Arguably the best part of this recipe. I use French's crispy fried onions.
Mushroom sauce
- Melt the butter in a large skillet. Once bubbling, add the mushrooms.
- Cook for 6 to 8 minutes, until reduced in size and golden. Add the minced garlic and cook until fragrant, just 2 to 3 minutes.
- For this next step, you can leave the mushrooms in the pan or make the cream sauce in a separate pan. As pictured, I like to make it in a separate pan while the mushrooms cook to cut down on active time. Start by toasting flour until it is golden.
- Slowly stir in the whole milk, whisking continuously to avoid forming lumps. Then whisk in the vegetable broth. Bring to a gentle simmer. Simmer until thickened enough to coat the back of a spoon without sliding off. Taste for salt and pepper.
Casserole assembly
- Lightly grease the casserole dish with oil or butter. Spread the green beans in a thin layer.
- Top the green beans with caramelized onions.
- Pour the thickened mushroom cream sauce on top of the onions. Spread the sauce to the edges so that the green beans are mostly covered.
- Sprinkle French fried onions on top. If assembling the casserole in advance, wait to add the onions until just before baking.
- Cover in foil for the first 15 minutes of cooking. This allows the casserole to warm up without burning the fried onions on top.
Expert casserole tips
- Trim fresh green beans: Always remove the ends and stems of green beans before cooking. I use my hands to do this but you can also use a knife to quickly slice off ¼ inch from each side of the green bean.
- Parboiled green beans: Just like when cooking pasta, make sure to boil the green beans in well-salted water at a rolling boil. The green beans are ready in just about 3 to 5 minutes when they are still vivid green but tender enough to pierce with a fork.
- Make it a classic green bean casserole: For a more traditional approach to this casserole, simply omit the caramelized onions.
- Quickly caramelize onions by sprinkling the onions with ⅛ teaspoon of baking soda. This cuts down onion caramelizing time to just 10-15 minutes! The onions break down more than traditionally caramelized onions, but still have that classic sweet flavor.
- Casserole size: This casserole works in most shapes and sizes of casserole dish. I like making it a 7x11-inch dish in order to have the most surface area to sprinkle with French-fried onions. However, it also works in deeper 2-quart dishes.
FAQ
Yes! Frozen green beans can be used in place of fresh in this casserole. Simply use an equal amount of frozen green beans by weight. Cook green beans according to package instructions before adding them to the casserole.
A few simple swaps can make this recipe dairy-free. Use unsweetened and unflavored non-dairy milk, such as soy milk, in place of whole milk. Use dairy-free butter or olive oil in place of butter.
The mushroom cream sauce can be made gluten-free by using an equal amount of gluten-free all-purpose flour blend in place of flour. French fried onions are made using wheat flour. I haven't come across a gluten-free fried onion but there are definitely recipes out there if you want to try your hand at homemade fried onions!
No, fresh green beans do not need to be soaked before cooking. They should be rinsed thoroughly and then added to a pot of boiling water to par-boil.
Make in advance and storage
Assemble the casserole in advance: Make the casserole according to the recipe but don't add the French fried onions. Cover tightly and store in the fridge for up to 3 days. Remove from the fridge and let come to room temp while the oven is preheating. Add the fried onion topping and cook according to recipe instructions.
Caramelized onions: Store cooked onions in the fridge for up to 3 days. I like to make a double batch of caramelized onions so that they can be used as a topping in other recipes or in mushroom cheesesteaks. Caramelized onions freeze well.
Leftovers: For best quality, keep leftovers refrigerated in a closed container for up to 3 to 4 days.
Freezing: Green bean casserole freezes well without the fried onions. Cook from frozen, covered, for 20 to 25 minutes before removing foil and topping with French onions. Cook an additional 10 minutes without foil.
Looking for more casseroles?
Serve fresh green bean casserole alongside instant pot mashed sweet potatoes, sourdough stuffing, vegan cornbread muffins and panko tofu cutlets or a well-rounded dinner or Thanksgiving meal.
Did you try this recipe? You can leave a star rating in the recipe card or a review in the comments below. Or check out my cookbook and keep up to date with my YouTube, Instagram, TikTok, or newsletter!
Recipe
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Fresh Green Bean Casserole with Caramelized Onions
Equipment
- 7x11-inch casserole dish or similarly sized dish, can use a 2-quart dish instead
Ingredients
- 1 tablespoon olive oil
- 1 ½ pounds sweet yellow onions sliced into thin strips
- ⅛ teaspoon table salt
- ⅛ heaping teaspoon baking soda
- 1 ½ pounds fresh green beans ends snapped off
- water to boil green beans
- 1 teaspoon kosher salt divided
- 2 tablespoons unsalted butter
- 8 ounces cremini mushrooms roughly chopped
- 2 cloves garlic minced
- 2 tablespoons all-purpose flour
- 1 and ¼ cup whole milk
- ¾ cup vegetable broth
- ½ teaspoon black pepper
- 1 cup fried onions such as French fried onions
Instructions
- To quickly caramelize onions: Heat a skillet over medium heat. Once hot, add the olive oil. Add sliced onions, ⅛ teaspoon salt, and baking soda. Saute for 2 to 3 minutes, until onions start to turn golden. Reduce to medium-low heat. Cook for just 10 to 15 minutes, stirring occasionally, for quick-caramelized onions. The onions are ready when golden and softened. See note #2 for why this method works.
- Preheat the oven to 400 degrees F.
- To parboil green beans: Meanwhile, fill a large pot with water. Add ½ teaspoon kosher salt. Bring to a boil over high heat. Add trimmed green beans and cook until vivid green but still crisp, about 3 to 5 minutes. Drain and set aside.
- To make the cream sauce: Heat a large skillet over medium heat. Add two tablespoons of butter. Once melted, add the chopped mushrooms. Cook for 6-8 minutes, until softened. Add the minced garlic and cook until golden and fragrant, about 2 to 3 minutes. Sprinkle in the all-purpose flour. Cook for another 2 minutes, stirring frequently to prevent burning.
- Using a whisk, slowly stir in the milk. Stir in the vegetable broth. Sprinkle with remaining ½ teaspoon salt and pepper. Once the mixture starts bubbling over medium heat, reduce to medium-low. Simmer until thickened, stirring occasionally, about 6 to 8 minutes. It should be thick enough to coat the back of a spoon without sliding off.
- Assembly: Lightly coat an 7x11 inch or 2-quart casserole dish with non-stick spray or oil. Evenly layer the cooked green beans across the bottom. Cover with the caramelized onions. Pour the sauce over the green beans and onions, spreading to fully cover the green beans. Sprinkle the top with the fried onions.
- Cover with foil. Bake at 400 degrees for 25 minutes total. Take the foil off for the last 10 minutes. The casserole is ready when it is bubbling and the fried onions are golden brown. Enjoy!
Notes
- Green beans: Frozen green beans can also be used. Cook according to package instructions before adding to the casserole dish.
- Quick caramelized onions: Heaping ⅛ teaspoon, as in somewhere between ⅛ and ¼ teaspoon. Baking soda causes the onions to break down much more quickly by raising their pH balance, resulting in caramelized onions that are ready in just 10-15 minutes. The onions are less visually attractive, but taste nearly the same as traditionally caramelized onions.
- Gluten-free option: You can use a gluten-free all-purpose flour mix in place of standard all-purpose flour in the sauce but French fried onions usually contain gluten.
- Vegan options: Use unsweetened, unflavored soy or almond milk and vegan butter or olive oil in place of whole milk and dairy butter.
- Make-ahead options: Make the casserole according to the recipe instructions but don't add the fried onions. Cover and store in the fridge for up to 3 days. Remove from the fridge and let come to room temp while the oven is preheating. Add the fried onion topping and cook according to recipe instructions.
- Leftovers: Keep leftovers covered and refrigerated for 3-4 days for best quality.
Molly says
Made this dish for my family’s Thanksgiving today! It was delicious. Made it dairy free with almond milk and vegan butter.