Side dish or vegetarian main? You decide! Either way, you are going to love this Keto Spinach Casserole. You start by sautéing onion and garlic and then adding spinach and cream cheese. The creamy texture is amplified by the addition of sour cream and heavy cream, and flavors are taken to the next level with the addition of gruyère and Parmesan cheese. The result? A deliciously decadent low carb casserole that never fails to delight.

Overhead photo of a keto spinach casserole in a white casserole dish with a cheesy spoon pull.

Every now and then, a recipe takes me by surprise. I knew I'd like this easy spinach casserole; I just had no idea how much!

For me, this recipe is enough to stand as a meal on its own. (Especially with a touch of bacon sprinkled on top. For a hearty dinner, try it with Keto Short Ribs or Keto Turkey Tenderloin.

This is also fabulous with steak! Try my Keto Steak Marinade - it is especially good with roasts and cuts like flank steak.

Ingredient Notes

Olive Oil - If you use extra virgin olive oil, be mindful of the smoke point.
Onion - White or yellow onion is great here. Red works in a pinch but is a bit jammier when cooked.
Garlic - I love the punchy flavor that fresh, minced garlic gives this dish; garlic powder works too.
Spinach - I like the ease of frozen spinach, but if you want to use fresh that is also an option. You will want to saute it until wilted, chop, and make sure you squeeze out as much liquid as you can.
Cream Cheese and Sour Cream - Make sure you use full fat.
Heavy Cream - If you want to reduce the calories, you could substitute ½ cup chicken broth for the heavy cream.
Gruyere - Swiss cheese would also be nice here.
Salt and Pepper - For a fun change, sometimes I use finely ground smoked salt in place of plain sea salt.
Parmesan - Freshly grated is best.

Tips and Variations

For easier cleanup, prepare this in an oven-safe skillet.
I often like to add ¼ teaspoon of cayenne pepper for an extra kick of heat.

How to Make Keto Spinach Casserole

Preheat - First, start by preheating your oven to 350° F and spraying a baking dish with cooking spray. I used a 9" x 9", but an 8" x 8" would work too. You could even make this in an oven-safe skillet to make it a one-pan meal.

Photo of spinach and cream cheese being added to sauteed onion and garlic in a skillet.

Saute - Heat the oil in a skillet and saute the onion over medium-high heat until tender. Add the garlic, and cook until fragrant, about 1 minute longer.

Reduce Heat - Add the spinach and the cream cheese. Cook, often stirring, until the cream cheese is fully incorporated.

Photo of melted cream cheese incorporated into chopped spinach in a skillet.

Photo of heavy cream and sour cream being stirred into chopped spinach and cream cheese.

Remove from Heat - Stir in the sour cream, heavy cream, Gruyere, salt, and pepper.

Photo of egg being stirred into a cheesy creamy spinach mixture.

Photo of shredded cheese, heavy cream, and sour cream being added to a chopped spinach and cream cheese mixture.

Photo of keto spinach casserole in a casserole dish.

Add Egg - Once these are incorporated, add the egg. (The sour cream and heavy cream will cool the mixture enough so that the egg doesn't scramble.)

Transfer - Transfer the mixture to the prepared dish.

Top and Bake - Top with the parmesan cheese and bake until golden brown.