This keto green bean casserole is a low carb take on the classic holiday side dish! Fresh green beans covered in a delicious mushroom sauce and topped with crispy onions, this is a guaranteed hit.
Although I have a slew of casseroles on here, the green bean kind is always a hit!
Why this recipe works
- Fresh and fast. No frozen or canned green beans here. It uses fresh ones, which makes them perfectly crisp and tender throughout.
- Golden and crispy on top. The key feature of any good green bean casserole is the crispy onion topping, and we do it low carb style!
- NO canned soup. A secret ingredient keeps it extra creamy in the middle, while keeping it carb free.
- Kid friendly. This is the dish to make the kids beg for seconds (and get a dose of greens!). It’s also a little more fun than other ways to eat green beans.
What I love about this casserole is that no one misses out on the classic Thanksgiving side dishes because of dietary restrictions. It’s perfect on its own or go the traditional route and serve it alongside some roasted turkey.
For the casserole
- Green beans. Fresh green beans, not frozen ones. Be sure to trim them all, too.
- Olive oil. To fry everything together.
- Onions. Caramelizes in the casserole, giving a slightly sweet flavor.
- Mushrooms. Pairs well with the other vegetables for the ultimate appetizer or side dish.
- Garlic. Minced garlic. You can use fresh or jarred.
- Butter. Either unsalted butter or salted butter can be used. If you use the latter, you can reduce or omit the salt.
- Heavy cream. My secret ingredient! Many green bean casserole recipes call for milk or half and half, but I find using heavy cream just gives it that richer and more delicious flavor.
- Vegetable stock. Any stock can be used.
- Salt and pepper. to taste.
For the crispy onion topping
While I’d love to top them with my keto onion rings, this topping yields thinner and crispier onions, perfect to top the beans!
- Onions. The thinner you slice the onions, the crispier the topping will be!
- Milk of choice OR heavy cream. To help the flour stick to the onions.
- Almond flour. Blanched almond flour, to give a mock batter for them. You can also try keto bread crumbs.
- Salt and pepper. To taste.
- Olive oil. To fry it all in!
How to make a keto green bean casserole
Step 1- Make the onion topping
Toss the sliced onions in the milk, almond flour, salt, and pepper, and set aside. Heat a non-stick pan with olive oil on medium heat. Once hot, add the seasoned onions and pan fry for 5-6 minutes, until cooked and golden. Remove from the heat and set aside.
Step 2- Cook the green beans
Lightly blanch the green beans by placing them in a deep pot of boiling water. Let simmer for 2-3 minutes, before removing from the heat and draining them. Place the beans in a mixing bowl and set aside.
Step 3- Make the filling
Now, heat the non-stick pan with oil on medium heat. When hot, add the onions and pan fry until tender. Add the mushrooms and garlic and cook for 2-3 minutes. Transfer the veggies into the bowl with the green beans and place the pan back on the heat. Add the butter, followed by the heavy cream and vegetable stock, and whisk together. Let the mixture simmer, to slightly thicken, before removing from the heat. Pour the mixture over the green bean mixture and mix well, until combined.
Step 4- Bake the casserole
Finally, lightly grease a medium baking or casserole dish. Pour the green bean mixture into it, and bake for around 25 minutes, until the edges bubble. Top with the fried onions and bake for a further 10 minutes.
Can I make this ahead of time?
You can prepare this casserole up to three days in advance. Simply prepare the casserole as instructed but keep the topping separate and refrigerate them both. When ready to serve, bring the casserole dish to room temperature, add the onion topping and bake for 30 minutes.
- To store: Leftovers should be stored in the refrigerator, covered, for up to 1 week.
- To freeze: Remove the casserole from the dish and place it in a shallow container. Cover it completely, then store in the freezer for up to 6 months.
- To reheat: Green bean casserole is best reheated in a preheated oven, for 10-12 minutes, until the sides are bubbling. If you’d like this quicker, just microwave it for 1-2 minutes, until hot.
More vegetable sides to try
Frequently Asked Questions
Green beans are a keto friendly vegetable, containing just 2 grams net carbs per 1 cup serving.
This recipe contains 4 grams net carbs per serving, compared to a traditional casserole that has over 50 grams of carbs.
Cream of mushroom soup is not keto friendly or suitable for a keto diet. It contains over 40 grams of carbs per serving, which can easily kick someone out of ketosis.
Keto Green Bean Casserole
- Preheat the oven to 180C/350F. Grease a medium sized baking dish and set aside.
- In a mixing bowl, add your onion topping ingredients and mix well, 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 heat up on medium. 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 into 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 and 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.
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