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Keto green bean casserole featured image

Keto green bean casserole recipe card

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  • Author: Sachi
  • Total Time: 60 minutes
  • Yield: 8 cups 1x
  • Diet: Diabetic


This keto green bean casserole is made from scratch with fresh green beans, creamy mushroom sauce and homemade fried onions. Enjoy!


Units Scale
  • 1 pound fresh green beans
  • 2 cups water and 2 cups ice for ice bath
  • 2 tablespoons salted butter
  • 12 ounces baby Bella or white mushrooms, sliced
  • a pinch of salt
  • a dash of black pepper
  • 1-2 sprigs of thyme
  • 1/3 cup dry white wine
  • 1/2 cup heavy cream
  • 1 teaspoon soy sauce (optional)
  • 1 teaspoon Worcestershire sauce
  • 1/4 cup grated cheese (Parmesan or Gruyere are nice)
  • 2 cloves garlic, minced
  • 1/2 cup yellow onion, thinly sliced
  • 1 cup canola oil


  1. Rinse and trim green beans, then cut them into bite-sized pieces about 1-2 inches long.
  2. In a large pot, bring a quart of water to a boil. While you wait for the water to boil, prepare an ice water bath of cold water and ice, in a large bowl. When the water comes to a boil blanch green beans for 2-3 minutes until they turn bright green. Use a strainer to transfer green beans to the ice bath for a minute or two to chill. This stops the cooking process, prevents them from overcooking, and helps them retain their bright green color and crispness. Drain green beans in a strainer. Do not leave them in the ice bath or they will become soggy. Set aside.
  3. In a skillet over medium-high heat, sauté mushrooms in butter with salt and pepper, and thyme. When the mushrooms absorb all of the butter, add white wine. Let the wine cook down until it reduces by half, about 5 minutes. Stir in heavy cream, soy sauce, Worcestershire sauce, grated cheese and garlic. Bring to a simmer, then remove from heat. 
  4. Fold green beans into mushroom sauce and transfer the mixture to a casserole dish to warm in a 300°F oven for 20 minutes while you prepare the crispy fried onions.
  5. Heat oil in a deep skillet or Dutch oven over medium-high heat. I used a cast iron skillet. When the oil shimmers, test a slice by frying it. It should bubble up and cook to a crisp in a minute or two. Working in batches, gently place onion slices in a single layer into the hot oil. Do not drop them into the oil as this can cause the hot oil to splash and burn someone. Don’t overcrowd the pan or the onions will steam and get soggy rather than crisp. Be patient, it only takes a minute or two. Use a whisk or spider to separate slices while they cook. Fry onion slices in hot canola oil, the oil needs to reach 350-375°F.  Fry for 2-3 minutes until golden brown and crispy. The onions will steam and the oil will bubble. You will know that the onions are just about finished cooking when the steaming and bubbling dies down. Transfer to a wire rack or paper towel-lined plate. Set aside.
  6. Before serving, top casserole with crispy onions and bake 5 more minutes.


  • Make ahead a day or two before. Just transfer to a casserole dish, cover and refrigerate until ready to bake.
  • For crisp, bright green beans don't overcook them.
  • Avoid soggy green beans. Don’t leave blanched green beans soaking in an ice bath. Strain immediately.
  • Avoid greasy mushrooms. Instead of adding more fat while cooking mushrooms, add liquid to help them cook.
  • Cook mushrooms as long as it takes to cook down the liquid, until you get golden-brown mushrooms. You can't overcook mushrooms, because they are fungi and fungi are made of chitin, rather than fiber. This makes them heat stable. They won't break down structurally with cooking the way meat, fruits and vegetables do.

  • Prep Time: 20 minutes
  • Cook Time: 40 minutes
  • Category: sides
  • Method: bake
  • Cuisine: American