Cheesy Keto Green Bean and Mushroom Casserole

Low-carb holiday favorite that’s creamy, cheesy, and delicious! This Cheesy Green Bean and Mushroom Casserole is the ultimate comfort food for your keto diet. It features fresh green beanscheddar cheese, and a creamy sauce made with heavy cream. The cheesy green bean casserole is topped with crispy onions for a satisfying crunch. 

Perfect for Thanksgiving table, Christmas table, or any festive occasion, this low-carb recipe is packed with flavor and perfect for your holiday table. Whether you’re making it for a crowd or meal-prepping for the week, this cheesy green bean casserole recipe is easy, gluten-free, and sugar-free.

A forkful of cheesy keto green bean casserole with mushrooms and crispy onion topping.
Cheesy Keto Green Bean Casserole with Mushrooms and Crispy Onion Topping

This delicious green bean casserole is more than just a holiday side dish to go with your Thanksgiving turkey. It’s a fantastic addition to your weekly dinner rotation, whether you’re prepping for a keto-friendly meal plan or looking for a comforting, cheesy side. 

Enjoy the best green bean casserole as a quick, low-carb side dish with roasted chicken, grilled steak, or even on its own for a light lunch. Packed with protein and flavor, this classic holiday side dish, made low carb, is perfect for any time of year!

If you’d like to see how I made this recipe, check out my quick YouTube video for helpful process shots and tips!

Ingredients

For the Casserole:

  • fresh green beans, trimmed and cut into bite-sized pieces
  • sliced mushrooms (white button or baby bella)
  • full-fat cottage cheese (optional)
  • heavy cream (optional for a creamier sauce)
  • shredded cheddar cheese or Mozzarella

For the Crispy Onion Topping:

  • onion
  • almond flour
  • grated Parmesan cheese
  • olive oil
Keto Green Bean and Mushroom Casserole topped with crispy onions in a white baking dish.
Low Carb Green Bean and Mushroom Casserole with Crispy Onion Topping

Instructions

  • Preheat the Oven: Set your oven to 375°F (190°C).
  • Cook the Vegetables: In a skillet, melt 1 tablespoon of butter over medium heat. Add the sliced mushrooms and sauté for 1–2 minutes.
  • Add the green beans and continue to sauté for 4–5 minutes until they are tender and golden brown. Remove from heat and transfer the vegetables to a small casserole or oven-proof baking dish.
  • Prepare the Creamy Sauce: In a bowl, whisk together cottage cheese, heavy cream (if using), sage, rosemary, and salt (optional). Adjust seasoning to taste. Pour the creamy mixture over the vegetables in the casserole dish. Sprinkle the shredded cheddar (or Mozzarella) cheese evenly over the top.
  • Make the Crispy Onion Topping: In a separate bowl, toss the thinly sliced onions with almond flour, grated Parmesan, and olive oil until well coated. Spread the onion mixture evenly over the top of the casserole.
  • Bake the Casserole: Place the casserole in the preheated oven and bake for 15–20 minutes, or until the cheese is bubbly and the crispy onion topping is golden brown.
  • Serve and Enjoy: Let the casserole cool for a few minutes before serving. This comforting, low-carb side dish is perfect for Thanksgiving, Christmas, or any holiday meal!
Overhead view of keto green bean casserole with a golden crispy onion topping.
Keto Green Bean Casserole with Mushrooms

Recipe Tips

For a festive holiday feast, start with a juicy roasted turkey as the centerpiece, seasoned to perfection with your favorite herbs. Pair it with this creamy Cheesy Green Bean and Mushroom Casserole with Keto Crispy Onion, which adds a comforting side dish packed with flavor. Add a burst of tangy sweetness with your Keto Cranberry Orange Relish to balance the savory dishes. For some heartiness, include the Keto Sausage Stuffing Muffins, which are the perfect low-carb alternative to traditional stuffing. Round out the meal with Keto Garlic Bread, an irresistible side that’s perfect for soaking up those holiday flavors. For dessert, treat your guests to Keto Pumpkin Spice Cheesecake Bites for a sweet, seasonal finish. This meal is guaranteed to be a hit and fits perfectly into a keto lifestyle while keeping the holiday spirit alive!

  • Dry the Green Beans: After blanching, pat the green beans dry with a paper towel to avoid excess moisture. This keeps the casserole creamy, not watery.
  • Boost the Creaminess: Add heavy cream for an extra-rich and silky texture.
  • Get Creative with Cheese: Swap out cheddar cheese for Parmesan, Gruyère, or Mozzarella for different flavors.
  • Crispy Topping Alternatives: For more crunch, replace the almond flour with crushed crispy pork rinds or crispy fried onions.
Partially eaten keto green bean casserole in a white baking dish on a wooden serving board.
Creamy Keto Green Bean and Mushroom Casserole Recipe for Low-Carb Holidays

Ingredient Swaps

  • Green Beans: Substitute with canned green beans for convenience. Just be sure to drain and rinse them well.
  • Mushrooms: Use white button mushrooms or skip them entirely and replace with zucchini or asparagus.
  • Cottage Cheese: Try cream cheese for an even richer base.

Storage and Reheating

  • Refrigerator: Store leftovers in an airtight container for up to 3 days.
  • Freezer: Freeze portions in a freezer-safe container for up to 2 months.
  • Reheat: Warm in the oven at 350°F (175°C) or microwave for a quick option.

FAQ

Q: Is this recipe just for holidays?
A: Not at all! This casserole is perfect for any occasion. It makes a great side dish for family dinners, meal prep, or cozy evenings at home. It pairs wonderfully with grilled or roasted meats, or enjoy it as a light vegetarian meal.

Q: Can I make this casserole ahead of time?
A: Yes! Assemble the casserole but keep the crispy onion topping separate. Add the topping just before baking to keep it crunchy.

Q: Is this recipe gluten-free?
A: Absolutely! The almond flour and keto-friendly ingredients make this dish completely gluten-free.

Q: Can I use canned green beans?
A: Yes, but for the best flavor, use fresh green beans. If you use canned, rinse them well to remove excess salt.

Q: What’s the carb count for this recipe?
A: This low-carb recipe contains just a few grams of net carbs per serving, making it perfect for a keto diet.

Q: Is this casserole kid-friendly?
A: Definitely! The creamy cheese and crispy topping make it a favorite for both kids and adults.


This Cheesy Green Bean and Mushroom Casserole is the perfect addition to your holiday table. From the creamy sauce to the crispy topping, this dish is loaded with flavor and texture. Whether you’re hosting a Thanksgiving dinner or looking for a quick weeknight side, this keto casserole recipe is sure to impress. Add it to your collection of keto recipes and enjoy the perfect balance of health and flavor!

Close-up of cheesy keto green bean casserole with crispy onions and mushrooms.
Keto Green Bean Mushroom Casserole with Crispy Onion Topping

More Keto Recipes

  1. Keto Sausage Stuffing Muffins
  2. Keto Garlic Bread Recipe
  3. Cottage Cheese Egg Muffins with Pancetta
  4. Keto Yorkshire Pudding (Almond Flour)
  5. Keto Pumpkin Spice Cheesecake Bites
A forkful of cheesy keto green bean casserole with mushrooms and crispy onion topping.

Cheesy Keto Green Bean and Mushroom Casserole

Author: Rally Rus
This Cheesy Green Bean and Mushroom Casserole with Keto Crispy Onion is a perfect low-carb side dish for Thanksgiving, Christmas, or any meal year-round. Packed with fresh green beans, sautéed mushrooms, and topped with a crispy onion crust, this keto-friendly, gluten-free, and high-protein recipe is a delicious way to enjoy a classic comfort food in a healthy way. Easy to prepare and bursting with creamy, cheesy flavors!
5 from 1 vote
Net Carbs: 5.5g
Print Recipe Pin Recipe
Prep Time 10 minutes
Cook Time 15 minutes
Total Time 25 minutes
Course Sides
Servings 2 servings
Calories 200.6 kcal
Shop my favorite keto-friendly essentials to make your low-carb journey smoother from my Amazon Store HERE.

Ingredients
 
 

For the Casserole:

  • 1 cup green beans trimmed and cut into bite-sized pieces
  • 1/2 cup mushrooms sliced, white button or baby bella
  • 1/4 cup full-fat cottage cheese
  • 2 tablespoon heavy cream optional for a creamier sauce
  • 1/4 cup cheddar cheese shredded, or Mozzarella
  • 1/2 teaspoon sage
  • 1/2 teaspoon rosemary
  • 1/2 teaspoon salt optional
  • 1 tablespoon butter for frying

For the Crispy Onion Topping:

  • 1/4 onion thinly sliced
  • 1 tablespoon almond flour
  • 1 tablespoon Parmesan cheese grated
  • 1 teaspoon olive oil

Instructions
 

  • Preheat the Oven: Set your oven to 375°F (190°C).
  • Cook the Vegetables: In a skillet, melt 1 tablespoon of butter over medium heat. Add the sliced mushrooms and sauté for 1–2 minutes.
  • Add the green beans and continue to sauté for 4–5 minutes until they are tender and golden brown. Remove from heat and transfer the vegetables to a small casserole or oven-proof baking dish.
  • Prepare the Creamy Sauce: In a bowl, whisk together cottage cheese, heavy cream (if using), sage, rosemary, and salt (optional). Adjust seasoning to taste. Pour the creamy mixture over the vegetables in the casserole dish. Sprinkle the shredded cheddar (or Mozzarella) cheese evenly over the top.
  • Make the Crispy Onion Topping: In a separate bowl, toss the thinly sliced onions with almond flour, grated Parmesan, and olive oil until well coated. Spread the onion mixture evenly over the top of the casserole.
  • Bake the Casserole: Place the casserole in the preheated oven and bake for 15–20 minutes, or until the cheese is bubbly and the crispy onion topping is golden brown.
  • Serve and Enjoy: Let the casserole cool for a few minutes before serving. This comforting, low-carb side dish is perfect for Thanksgiving, Christmas, or any holiday meal!
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YouTube Video

Notes

Recipe Tips
For a festive holiday feast, start with a juicy roasted turkey as the centerpiece, seasoned to perfection with your favorite herbs. Pair it with this creamy Cheesy Green Bean and Mushroom Casserole with Keto Crispy Onion, which adds a comforting side dish packed with flavor. Add a burst of tangy sweetness with your Keto Cranberry Orange Relish to balance the savory dishes. For some heartiness, include the Keto Sausage Stuffing Muffins, which are the perfect low-carb alternative to traditional stuffing. Round out the meal with Keto Garlic Bread, an irresistible side that’s perfect for soaking up those holiday flavors. For dessert, treat your guests to Keto Pumpkin Spice Cheesecake Bites for a sweet, seasonal finish. This meal is guaranteed to be a hit and fits perfectly into a keto lifestyle while keeping the holiday spirit alive!
  • Dry the Green Beans: After blanching, pat the green beans dry with a paper towel to avoid excess moisture. This keeps the casserole creamy, not watery.
  • Boost the Creaminess: Add heavy cream for an extra-rich and silky texture.
  • Get Creative with Cheese: Swap out cheddar cheese for Parmesan, Gruyère, or Mozzarella for different flavors.
  • Crispy Topping Alternatives: For more crunch, replace the almond flour with crushed crispy pork rinds or crispy fried onions.
Ingredient Swaps
  • Green Beans: Substitute with canned green beans for convenience. Just be sure to drain and rinse them well.
  • Mushrooms: Use white button mushrooms or skip them entirely and replace with zucchini or asparagus.
  • Cottage Cheese: Try cream cheese for an even richer base.
Storage and Reheating
  • Refrigerator: Store leftovers in an airtight container for up to 3 days.
  • Freezer: Freeze portions in a freezer-safe container for up to 2 months.
  • Reheat: Warm in the oven at 350°F (175°C) or microwave for a quick option.

Nutrition

Serving: 1servingCalories: 200.6kcalCarbohydrates: 8gNet Carbs: 5.5gProtein: 10.2gFat: 14.9gSaturated Fat: 7.3gSodium: 224.2mgPotassium: 267.2mgFiber: 2.5gSugar: 4.2gVitamin A: 798.1IUVitamin C: 8.3mgCalcium: 192.7mgIron: 0.9mg
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Did you make this recipe and love it?Please let me know in the comments below how it turned out: Leave a Review!

One Comment

  1. 5 stars
    This worked exactly as written, thanks!

5 from 1 vote

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