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This low carb Green Bean Casserole will help you maintain your holiday traditions without sacrificing any flavor! The topping is reminiscent of French fried onions. Yum! THM S
Our family’s Christmas traditions
Growing up, we didn’t have any hard and fast Christmas dinner traditions. Christmas dinner varied by the year depending on which side of the family we celebrated with. With my dad’s family we usually had subs for Christmas lunch, and Christmas Eve was the time to bring out all our favorites:
- frozen eggnog,
- buckeyes,
- all the Christmas candy and decorated cut out cookies,
- Muenster cheese,
- Chicken in a Biscuit crackers,
- and maybe some grilled shrimp.
With my mom’s side of the family we often had a more traditional turkey or ham dinner on Christmas Day, complete with mashed potatoes and gravy, salad, dinner rolls, and pie, but even then there’s not one dish in particular that always appears on the Christmas table.
I’ve heard that some families are very attached to certain dishes at Christmas, and green bean casserole is one such dish that I’ve heard mentioned over and over again so I thought I should offer a healthy alternative. If you’re headed to a Christmas feast and need a side dish that everyone (including you) can enjoy, take this green bean casserole! Its creamy mushroom soup sauce and “French fried onion” topping will be a hit!
How to navigate holiday dinners
I wrote a whole post about this RIGHT HERE, but I’ll share a few of my tips in this post too:
-
- If you don’t think you’ll have many healthy options, eat something before you go so you’re not ravenous at the party. I recommend something protein-based with some satiating fats to curb cravings.
- Take something “safe” along that you know you can eat. Salad, a veggie tray, a healthy side dish like this green bean casserole – something to accompany the meat that will probably be served.
- When fixing your plate, start with protein. Turkey, ham, or if you’re at a finger food party, summer sausage, cold cuts, or chip dips that look safe. Cheese slices can work too.
- Add veggies (and veggie dip is often fairly safe as well). Feel free to load up on plain cooked veggies and salad as well (no croutons!).
- Stay away from breads, crackers, sweet sauces, carb-y casseroles (i.e. green bean casseroles with Ritz cracker or French onion toppings), and of course cookies, pies, cakes, and any other sweets made with sugar.
- If you want to splurge, don’t throw everything you know out the window and eat everything in sight! Keep your splurge controlled and hop right back into your healthy eating lifestyle as soon as you get home.
For example, if we were having subs on Christmas Day, I would bring a Joseph’s pita or lavash bread and stuff it with mayo, meat, cheese, lettuce, and mustard.
For Christmas Eve, I would have grilled shrimp, cheese, and some of my healthy buckeyes, truffles, or peanut butter fudge (or all of the above). If I felt like it, I would make some healthy frozen eggnog, but in real life, I’ll probably have a small glass of the sugary stuff as a once-a-year treat (see point #6 above).
For a more traditional Christmas dinner, enjoy the turkey or ham, eat plenty of salad and cooked veggies (stay away from vegetable casseroles with carb-y toppings), and bring a healthy dessert to share!
Frozen vs canned green beans
I have not tried canned green beans in this recipe, but I imagine that they would work and you would not have to bake the casserole as long. I would drain the beans well, mix them with the mushroom soup, and spread them into the pan. Skip the first bake with the foil and just add the topping right away, then bake uncovered for 30-40 minutes until the casserole is heated through. If you try this, comment below and let me know how it goes!
Be sure to check the Notes section of the recipe for a gluten free suggestion!
As always, check out the Notes section of the recipe for helpful info and answers to frequently asked questions!
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New and improved
This is an update of the Green Bean Casserole recipe on page 124 of Necessary Food. This recipe is a double batch made in a larger pan so you can feed a crowd. I added mushrooms to the soup for a mushroom soup flavor, added an onion topping reminiscent of French fried onions, and bumped up the spice and flavor.

Green Bean Casserole
- Total Time: 1 hour 30 minutes
- Yield: 12-15 servings
Description
This low carb Green Bean Casserole will help you maintain your holiday traditions without sacrificing any flavor! The topping is reminiscent of French fried onions. Yum! THM S
Ingredients
- 3 12-ounce bags frozen green beans (thawed)
MUSHROOM SOUP:
- 8 ounces fresh mushrooms
- 1 cup light sour cream
- 3/4 cup plain unsweetened almond milk
- 1/4 cup oat fiber
- 2 teaspoons salt
- 1 teaspoon onion powder
- 3/4 teaspoon black pepper
TOPPING:
- 1 large yellow onion (sliced)
- 2 tablespoons salted butter
- 1 cup shredded sharp cheddar cheese
- 6 Light Rye Wasa or Ryvita crackers (crushed – I used my Tupperware Smooth Chopper)
Instructions
Blend the mushroom soup ingredients together until smooth – I used my Vitamix blender. Mix the soup with the green beans in a large mixing bowl and spread into a greased 9” x 13” glass baking pan. Cover with foil and bake at 350° for 40 minutes.
While the casserole is baking, make the topping. Sauté the sliced onion in the butter in a skillet until nicely browned (this takes a while). I like to start cooking the onions with a lid on the pan to expedite the cooking process, then remove it after the onions are soft to reduce any liquid and let the onions brown. When the onions are brown, take the pan off the heat and let the onions cool before adding the cheese and cracker crumbs.
When the casserole has finished its first 40 minutes of baking, remove it from the oven and take the foil off. Mix the shredded cheddar and cracker crumbs into the cooled onions, then spread the topping evenly over the casserole.
Bake uncovered for another 20 minutes or until the beans are tender and the topping is golden brown.
This green bean casserole is best fresh as most things are, but you can make it ahead and reheat if you need to. You could possibly do the first bake ahead of time, then add the topping and do the final bake to warm it through before serving. (If the casserole is cold from the fridge, you may need to bake more like 30-40 minutes to warm it through.) That may be better than baking it all the way, then baking it again to heat it.
Notes
Frozen vs canned green beans: I have not tried canned green beans in this recipe, but I imagine that they would work and you would not have to bake the casserole as long. I would drain the beans well, mix them with the mushroom soup, and spread them into the pan. Skip the first bake with the foil and just add the topping right away, then bake uncovered for 30-40 minutes until the casserole is heated through. If you try this, comment below and let me know how it goes!
Wasa or Ryvita crackers: If you need to be gluten free, omit these and try using some additional cheese instead. I often find these crackers at salvage/discount stores. Walmart or local grocery stores usually carry a variety or two as well.
Allergy info: egg free and nut free – use carton coconut milk instead of almond milk if needed (most people with tree nut allergies can have coconut products, but confirm with your doctor). For a gluten free option, use gluten free oat fiber and follow the note above to replace the Wasa crackers.
This is an update of the Green Bean Casserole recipe on page 124 of Necessary Food. This recipe is a double batch made in a larger pan so you can feed a crowd. I added mushrooms to the soup for a mushroom soup flavor, added an onion topping reminiscent of French fried onions, and bumped up the spice and flavor.
This recipe was originally published to the blog on December 22, 2015. It was updated November 2021.
- Prep Time: 30 mins
- Cook Time: 60 mins
- Category: Side Dish
- Method: Bake
- Cuisine: THM S, low carb
Keywords: thm, trim healthy mama, thm green bean casserole, low carb green bean casserole, gluten free green bean casserole, healthy green bean casserole, thm thanksgiving recipes
This recipe was originally published to the blog on December 22, 2015. It was updated November 2021.
I would like to make this for Thanksgiving dinner, but our son-in-law doesn’t like mushrooms. Would it work to leave them out of the soup?
Well it certainly wouldn’t be mushroom soup, but it would probably still work. 😉
I only have unsweetened vanilla almond milk :/ any ideas to substitute? And how many cans of green beans would you use to substitute? I’m sure I could just eyeball it too. Thanks so much for the recipe!
Half and half or part cream, part water would work in place of the almond milk. Just use 4 cups of drained, canned green beans. =)
My favorite green bean casserole! I’ve made this recipe several times and it never disappoints.
★★★★★
Could I add mushrooms to this?
I’m sure you could! It might be a little more watery, but I love the idea!
Could you use gluccie instead of oat fiber?
I’m afraid the result would be slimy, and you’d definitely need to use much less gluccie than you would oat fiber. If you don’t have oat fiber, I’d just leave it out and expect a slightly runnier sauce. 🙂
I just found this site and am excited to be learning about THM. Ordered your cookbook already & am waiting on it to arrive.
I hope you enjoy it, Betty!
Would fresh green beans work?
I don’t recommend that – it would take a really long time for them to get tender.
Hi Briana, I’m in Australia and we don’t have those crackers available as far as I know. Do you think if I used the baking blend, mixed with the cheese and butter, it would work?
It definitely wouldn’t have the same crunch, but it might work. I hesitate to say, “Go for it!” having never tried it myself. If you try it, let me know how it works!
I love this recipe more than the regular one. It is super delish. It is so good, I have it more than a once a year treat. Now I spoil myself regularly. Thanks!
★★★★★
Very good. Had pork rind crumbs on hand so used t.hose. Delicious
★★★★
Would sourdough bread crumbs be suitable? I am still learning this THM and I am excited about it!
Hi Ruth! Sourdough bread (as long as it is true sourdough – a lot of sourdough breads aren’t actually on plan for THM due to added ingredients or not a long enough culture time) is an E, and this casserole is an S, so using sourdough crumbs would make this a crossover. Still healthy, but not weight loss promoting. 🙂