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This keto green bean casserole recipe features tender green beans in a creamy mushroom sauce and topped with crispy onions. It’s guaranteed to be a family favorite! 3 grams net carbs.
Need more keto casserole recipes? Try my keto chicken casserole, keto taco casserole, and keto pizza casserole next.
Come the holidays, my low-carb green bean casserole becomes a hot commodity.
Traditional green bean casserole, while delicious, is not keto-friendly. So, I made a few low-carb swaps and now it’s my most highly requested casserole recipe!
Table of Contents
Why I love this recipe
- It’s fresh AND fast. No frozen green beans or canned soup here!
- That addictive crunch topping! We all know the best part about green bean casserole is the crispy onion topping–and mine is the best.
- Kid-friendly. If you’ve been wondering how to get kids to eat their greens, let this recipe do the work for you.
- Easy to make ahead. When I visit home for the holidays, I dread squeezing a full Thanksgiving dinner into my mom’s tiny kitchen. So, I make this casserole in advance and pop it in the oven right before dinner.
Ingredients needed
- Fresh green beans. Preferably fresh, trimmed green beans.
- Oil. To fry.
- Onions. Caramelizes in the casserole, giving a slightly sweet flavor.
- Mushrooms. A must for green bean casserole!
- Garlic. I used jarred garlic, but fresh works too.
- Butter. I used unsalted butter. If you use salted butter, reduce the amount of added salt.
- Heavy cream. My secret ingredient! Many green bean casserole recipes call for milk or half and half, but I find using heavy cream gives it a richer texture akin to condensed cream of mushroom soup.
- Vegetable stock. Look for low-sodium stock. You can also use chicken broth or mushroom broth.
- Salt and black pepper. To taste.
For the fried onions:
- Onion slices. The thinner you slice the onions, the crispier the topping will be!
- Milk OR heavy cream. To help the flour stick to the onions.
- Almond flour. To dredge the onions. Use blanched almond flour, almond meal, or make keto bread crumbs with crushed pork rinds.
- Salt and black pepper. To taste.
- Oil. To fry.
How to make keto green bean casserole
I’ve included step-by-step photos below to make this recipe easy to follow at home. For the full printable recipe instructions and ingredient quantities, scroll to the recipe card at the bottom of this post.
Step 1- Prep work. Preheat the oven to 180C/350F and grease a casserole dish.
Step 2- Prepare the onions. In a small bowl, combine the onion topping ingredients and toss to coat.
Step 3- Fry the onions. Heat oil in a large skillet over medium heat. Once hot, add the onion mixture and fry for 4-5 minutes, until golden. Set aside.
Step 4- Cook the green beans. In a large pot, boil 3-4 cups of water. Once boiling, add the green beans and blanch them in the water for 3 minutes. Drain and transfer to a large bowl.
Step 5- Cook the mushrooms. Add olive oil to a large skillet over medium heat. Sauté the onions for 5 minutes, then add the garlic and mushrooms and sauté for 3-4 minutes. Transfer the veggies to the bowl with the green beans.
Step 6- Build the sauce. Return the skillet to the heat and add butter. Add the stock, cream, salt, and pepper, and simmer for 3-4 minutes. Pour the soup mixture over the green beans and stir to combine.
Step 7- Bake. Transfer the green bean mixture to the baking dish. Bake for 35 minutes, then sprinkle with the crispy onions. Return the dish to the oven and bake for 10 minutes or until bubbling.
Arman’s recipe tips
- Make it in advance. Prepare the casserole and store the casserole and toppings separately in the fridge. Refrigerate it for up to three days, then let it come to room temperature for 20 minutes before baking as directed.
- Make a creamier sauce. Add a dollop of softened cream cheese and a handful of shredded mozzarella cheese. You can thank me later!
- Add bacon. Isn’t everything better with bacon?
Storage instructions
To store: Keep leftovers in an airtight container in the refrigerator for up to one week.
To freeze: Transfer the leftovers to a freezer-safe container and freeze for up to six months.
Reheating: Microwave single-servings in 30-second intervals or place in a casserole dish and bake in a preheated oven until warm.
Frequently asked questions
Green beans are a keto-friendly vegetable, containing just 2 grams of net carbs per 1 cup serving.
This recipe contains 4 grams of net carbs per serving, compared to a traditional casserole that has over 50 grams of carbs.
More keto-friendly holiday recipes
- Cauliflower mac and cheese
- Keto mashed potatoes
- Cauliflower potato salad
- Keto rolls
- Or any of my keto side dishes
Keto Green Bean Casserole
Ingredients
- 3 cups green beans washed and trimmed
- 2 tablespoon olive oil
- 1 small onion sliced
- 1 cup mushrooms sliced
- 2 tablespoon garlic minced
- 4 tablespoon butter
- 1 cup vegetable broth
- 1 cup heavy cream
- 1 teaspoon salt
- 1 teaspoon pepper
For the onion topping
- 1 medium onion sliced
- 2 tablespoon milk of choice I used unsweetened almond milk
- 1/4 cup almond flour
- 1 teaspoon salt
- 1 teaspoon pepper
- 1 tablespoon olive oil
Instructions
- Preheat the oven to 180C/350F. Grease a medium sized baking dish and set aside.
- In a mixing bowl, make the crunchy onion topping. Add your onion, milk, almond flour, salt, pepper, and olive oil, and mix until all the onions are coated.
- Heat your oil in a non-stick pan on medium heat. When hot, add the onion mixture and stir fry for 4-5 minutes, until golden. Remove from the heat and set aside.
- In a deep pot or saucepan, heat up 3-4 cups of water until boiling hot. When hot, add the green beans and blanch them, by letting them simmer for 3 minutes. Drain and transfer into a large mixing bowl.
- In a non-stick pan, add the olive oil and place over medium heat. When hot, add the sliced onions and saute for 5 minutes. Add the garlic and mushrooms and saute for an extra 3-4 minutes. Transfer the vegetables to the bowl with the green beans.
- Place the pan back on the heat and add the butter. Once sizzling, add the vegetable stock, heavy cream, salt, and pepper, and let it simmer for 3-4 minutes, to thicken. Remove from the heat, pour over the green bean and vegetable mixture, and mix well.
- Transfer the green bean casserole to the greased baking dish. Bake for 35 minutes, before removing from the heat and topping with the crispy onions. Place back in the oven for a further 10 minutes, until the edges are bubbling.
This is the first time I’ve enjoyed eating a green bean casserole. Delicious!
I’m now following your Instagram because of this recipe haha I love it!
I thought the same thing about the onions and then realized you cook the topping onions first and then in step 5 you are cooking the onions that are for the casserole along with the mushrooms and garlic. The crispy onions that you cooked first are then place on the top of the casserole and put back in the oven as indicated in step 7. I hope that helps.
Do you have a video of this recipe? If not, can you please do one? I’m failing miserably at the onions. They look SO GOOD in the photos and… I am inept at making keto crispy onions. 🙁
Don’t understand directions. Do you cook onions twice?
Hi J- The onions have been cooled since they have been prepped first, so they are re-heated once you add them to the casserole.