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 gruyere 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!

It makes sense given how much I love all the ingredients, but this simple dish blew me away. I think you will love it too!

Ingredients for Making Spinach Casserole Keto Style

Olive Oil - I used regular olive oil, not extra virgin. If you use extra virgin, 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 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 - I like the richness heavy cream gives this dish. If you want to reduce the calories of it for any reason, you could substitute ½ cup chicken broth for the heavy cream.
Gruyere - Gruyere cheese gives this casserole a burst of flavor that I love. Swiss cheese would also be nice here.
Salt and Pepper - Tri-colored fresh ground pepper is great in this recipe. For a fun change, sometimes I use finely ground smoked salt in place of plain sea salt.
Parmesan - Fresh grated is best.

Photo of a keto quickstart guide with the description of the guide on the right.

Serving Suggestions

Low Carb Spinach Casserole is hearty enough to stand as a meal on its own. 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.

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.

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.

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

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.

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

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

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.)

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

Transfer - Transfer the mixture to the prepared dish.

Photo of keto spinach casserole in a casserole dish.

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