Creamy Keto Green Bean Casserole with the Best Crispy “Onion” Topping
This Keto Green Bean Casserole has all the creamy, cozy flavor of the classic dish—just made low carb and completely gluten-free. A rich homemade mushroom sauce, tender green beans, and a crunchy “onion” cheese topping come together for a side that’s perfect for holidays or any comfort-food meal.
Servings: 12
Calories: 246kcal
Ingredients
- 3 cans french style green beans or cut green beans, drained
- 2 cups diced mushrooms
- 2 garlic cloves
- 1/3 cup diced onions
- 3 tbsp butter
- 2 cups chicken broth
- 1 cup heavy whipping cream
- 1/2 tsp salt
- 1 oz cream cheese, softened
- 1/2 tsp pepper
- 1/4 tsp nutmeg
- 3/4 cup cheddar cheese
- 1/4 cup mozzarella cheese, shredded
For the crunchy topping:
- 2 cups sharp cheddar cheese, shredded
- 1 ½ tablespoon onion, minced
- 1 tablespoon parmesan cheese, grated
- 1 tsp Italian seasoning
Instructions
- Preheat your oven to 350°F, then grease a 9×13 casserole dish so it’s ready to go.
- In a large skillet, melt 3 tablespoons of butter and add mushrooms, onion, minced garlic, salt, pepper, and nutmeg.
- Sauté on medium heat for 8-10 minutes until the onions are translucent and the mushrooms are soft.
- Add the chicken broth, cream cheese, and heavy whipping cream, stirring until the cream cheese melts and everything comes together. Stir in the cheddar and mozzarella, then let the mixture simmer on medium-high with the lid off until it reduces and thickens - about 25 minutes. If your stovetop runs cooler and it’s still thin, just keep simmering a few extra minutes. If you prefer a smoother texture, you can blend the mushrooms with an immersion blender, once the sauce has thickened
- While the sauce is cooking down, line a baking sheet with parchment. Scatter the shredded cheese, minced onion, Parmesan, and Italian seasoning evenly across the sheet.
- Bake for 8–12 minutes, just until the cheese melts and gets nicely golden. It’ll come out as one big crispy sheet.
- Let the cheese sheet cool completely, then break it into small pieces. Lay them on paper towels to soak up any extra oil—they’ll crisp up even more as they cool.
- In a greased 13 X 9 baking dish, add 1 ½ cans of the green beans (drained), then add the mushroom soup mixture and sprinkle ¾ cup of shredded cheddar cheese on top.
- Add the rest of the green beans, then top with the shredded mozzarella cheese.
- Bake the casserole for 25 minutes, then carefully remove it from the oven. Add the crispy cheese topping, and return it to the oven for about 5 minutes—just long enough to warm the topping slightly without melting it.
- Allow to sit for 5 minutes before serving, then dig in! Enjoy!
Notes
• Sauce consistency: If your sauce isn’t thickening, just keep simmering with the lid off. I’ve tested this on several stovetops, and some just need a few extra minutes.
• Too thick? A splash of chicken broth will loosen it right up. Add a little at a time until it’s where you like it.
• Fresh or frozen beans: Fresh green beans stay very firm in this casserole. Even blanching won’t soften them enough. If you want to use fresh ones, you’ll need to steam or boil them until tender before adding them to the casserole. And if you’re a Southern cook, you already know: green beans get boiled a good long while before they ever hit a casserole. Tender is the goal here, not crisp.
• Crispy topping tip: Let the cheese sheet cool completely before breaking it into pieces. It always crisps up more as it cools.
• Make-ahead option: If you want to prep this early, assemble everything except the topping. Add the crispy topping right before the final bake so it stays crunchy.
• Half batch: A 9×9 dish works perfectly if you’re making a smaller pan. Just scale the topping down a bit so it fits.
Nutrition
Calories: 246kcal | Carbohydrates: 7g | Protein: 10g | Fat: 21g | Fiber: 2g
