Keto Green Been Casserole with Crispy Fried Onions
Side Dishes 14 comments

Keto Green Bean Casserole

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Try the holiday classic in this low carb, keto recipe! Keto Green Bean Casserole has all the elements you love, including a crispy fried onion topping!

Keto Green Been Casserole with Crispy Fried Onions
Keto Green Been Casserole with Crispy Fried Onions

I don’t know what it is about this casserole, maybe it’s the mushrooms, perhaps it’s the fried onions (yes!), maybe it’s just all the holiday memories. Somehow this creamy and crispy green bean mashup always hits the spot.

Read on to see how to make a treat that’s usually carb heavy keto friendly.


Smoked Salt

I love this alder smoked salt and it is my most frequently used seasoning, by far! This is my everyday salt when I’m cooking and it adds a really nice depth of flavor to this casserole. Think of the smokey pork and beans or ham and beans combos that are so classic. This smokey salt helps add that rich flavor to this low carb grean bean casserole recipe. Give it a try!

Whey Protein

This is what gives our Keto Green Bean Casserole the crispy top! Lightly coat the onions in this powdered protein and it adds a crispy crunch bite! This is good for frying lots of things as well as baking – I use it in cakes and baked donuts, etc. It’s a great ingredient to have in your keto pantry!


Keto Green Bean Casserole is pretty darn easy to make! I’ve used fresh vegetables to make it but you could always used jarred or canned to make it even easier.

The onions should be sliced very thinly to make them spread as far as possible since they’re the highest carb element. Use a great knife and take your time 🔪. Alternatively, use a mandoline to get beautiful, thin slices.

Frying the onions is the most difficult part of this recipe. I filled a frying pan with a shallow layer of oil rather than deep frying. Fry your onions in smaller batches and drain well on a paper towel to remove excess oil.

Keto Green Been Casserole Crispy Fried Onions draining on a paper towel
Keto Green Been Casserole Crispy Fried Onions draining on a paper towel


  • Nonstick pan
  • Caserole dish
  • Mandolin (optional)
  • Knife 🔪
  • Cutting board
  • Paper towels for removing excess oil


This is a pretty straightforward recipe, but there’s always something that can go wrong in the kitchen! Let’s try to anticipate an issues that can come up and head them off at the pass!

Why is my sauce clumpy?

The cream cheese we add to help thicken up the sauce can be a little difficult to combine. It helps to have the cream cheese at room temperature before making your sauce. You can warm in the microwave, if you’re starting with it straight from the fridge. Also, be sure to whisk as you cook the sauce to break up any clumps. I abhor dirtying anything I don’t have to but you could always throw it into the blender if it refuses to cooperate!

Why are my onions burning?

Onions are high in sugar content (boo!) so they can cook up pretty quickly when you’re frying. I recommend cooking one onion piece and trying to make sure your oil is hot enough. If it browns quickly while leaving the onion kind of raw, you’ll want to turn the oil down. If it seems to take forever to brown, turn up the temperature.

What if I don’t want to add the fried onions?

These would be absolutely delicious as green beans and mushrooms in the cream sauce. If you’re using fresh veggies and cooking them right before dinner you could just toss the veggies back into the pan with the cream sauce and serve immediately. This would also lower the carbs in this recipe.

What alternatives are there for a crispy topping?

You could always use breadcrumbs either from keto bread or keto tortillas to make a breadcrumb topping for this as a casserole.


How to serve Keto Green Bean Casserole:

  • The classic – this is perfect for Thanksgiving 🦃, Christmas and Easter
  • Perfect for a Sunday dinner, it would be delicious with some pork tenderloin or a rotisserie chicken!
  • Perfect for a potluck or to take to a party
Keto Green Bean Casserole being served with a spoon Starfish in the Kitchen
Keto Green Bean Casserole with crispy fried onion topping

What should I drink with Keto Green Bean Casserole?

How about some white wine or bubbly 🥂 to go with the holiday meal? It is great with poultry and helps cut some of the richness of dishes like this.


Keep extras in the fridge for all those amazing leftovers! Somehow the flavors seem to get better and better as they sit in the fridge.


Keto Green Bean Casserole served in a white dish. Starfish in the Kitchen

Keto Green Bean Casserole

Try the holiday classic in this low carb, keto recipe! Keto Green Bean Casserole has all the elements you love, including a crispy fried onion topping!
5 from 5 votes
Prep Time 10 minutes
Cook Time 40 minutes
Course Side Dish
Cuisine American
Servings 8
Calories 151 kcal


  • Cutting board
  • Knife
  • Mandolin (optional)
  • nonstick pan
  • Casserole dish


  • 24 ounces green beans trimmed and cut into smaller pieces
  • 8 ounces mushrooms sliced thinly
  • 1/2 medium onion sliced thinly
  • 1.5 tablespoons butter for sauteing mushrooms
  • 1/2 cup water
  • 2 tablespoons whey protein for coating onions
  • avocado oil for trying onions, enough to cover pan
  • 1/2 cup chicken stock
  • 1/2 cup heavy whipping cream
  • 2 ounces light cream cheese room temperature
  • smoked salt to taste
  • black pepper to taste


  • Slice the mushrooms thinly
    Keto Green Been Casserole thinly sliced mushrooms
  • In a nonstick skillet, saute the mushrooms in butter on medium heat until lightly browned, seasoning with some salt and pepper
  • While mushrooms are cooking, trim and cut green beans into bite sized pieces
    Keto Green Been Casserole cut up green beans
  • When mushrooms are browned, add to casserole dish
  • Add 1/2 cup of water to the nonstick pan along with green beans and cover. Stir occasionally and check for doneness, I prefer a softer texture so I cook until there's just a little bite left in them. Add salt and pepper to beans.
  • Add cooked beans to casserole dish with mushrooms
  • Add chicken stock, heavy whipping cream and cream cheese to the nonstick pan. Cook on medium heat until sauce is thickened and bubbly. Add a little salt and pepper.
  • Pour finished sauce over the mushrooms and beans and mix well. Some liquids from the beans and mushrooms will mix and make a beautiful sauce. Give a quick taste and add salt and pepper if needed. (At this stage the casserole can be refrigerated if making ahead.)
  • Cook the casserole for 15-20 minutes in a 350 degree F oven or until everything is warmed through.


  • While the casserole bakes, we'll make the onion topping. Prepare a dish lined with paper towels for the fried onions.
  • In a smaller nonstick pan, add about 1/4 inch layer of cooking oil and heat until shimmering (not smoking) start off at medium heat.
  • Add 2 tablespoons of whey protein to a small dish. Dredge about 1/4 of the thinly sliced onions in the whey.
  • Test the oil temperature with one piece of onion. If it browns too quickly, turn the temperature down. If it browns very slowly, you'll need to turn the temperature up.
  • When the oil is hot enough, add the prepared onions to the pan. Allow to brown and then flip to brown the other side. Carefully remove the onions and place on the paper towels to drain.
    Keto Green Been Casserole Crispy Fried Onions draining on a paper towel
  • Repeat in small batches until all of the onions are fried. Add a touch of salt to the onions.
  • When the casserole is warmed and bubbly, removed from the oven, top with fried onions and serve! (I prefer to fry the onions immediately before serving. If you've made them ahead, add to the top of the casserole 5-10 minutes before serving
    Keto Green Been Casserole with Crispy Fried Onions


The carbs on this are a pinch higher than I usually go for; if you like mushrooms adding more mushrooms and fewer green beans would help lower the carb count on this dish.
Nutrition information from Cronometer.  Please calculate macros with your specific ingredients.
Keyword Chrstmas, Thanksgiving


  1. This looks delicious! I can’t wait to try. I love that this has real ingredients and not canned soup. Thanks for sharing!

  2. 5 stars
    Delicious. Great photos. We all love french beans in my family. Especially the kids. Would be a great side for a roast dinner.

  3. Looks delicious! And unique way to use whey protein

  4. 5 stars
    Love the tips on frying onions! Sounds simple but it’s true! You don’t know how often I’ve burned onions! Love this recipe !!

  5. 5 stars
    My boyfriend’s parents are keto, and this will be the first keto Thanksgiving we are having. I will have to try this recipe out! Thank you for sharing!

    • Thanks so much, Cassie, I’m so glad this will help you celebrate the holiday with them! I hope you check out the keto holiday stuffing and jellied cranberry sauce too! Happy Thanksgiving to you!

  6. 5 stars
    One of these evenings‍… I love anything mushroom and your recipe sounds delicious!

  7. 5 stars
    I love this recipe! Definitely trying it with smoked salt next time!

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