Keto Zucchini Casserole – Creamy, Cheesy, and Low-Carb Comfort

This Keto Zucchini Casserole is the kind of weeknight dinner that makes everyone happy. It’s creamy, cheesy, and full of fresh zucchini, but still light enough to keep you on track. You don’t need fancy ingredients or a lot of time—just simple pantry items and a skillet.

The best part? It reheats beautifully for easy lunches. If you’re craving cozy comfort without the carb crash, this casserole is a great choice.

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Keto Zucchini Casserole – Creamy, Cheesy, and Low-Carb Comfort

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Prep Time 15 minutes mins

Cook Time 30 minutes mins

Total Time 45 minutes mins

Servings: 6 servings

Ingredients
Method

Ingredients

  

• 3 medium zucchini (about 1.5–2 pounds), sliced into 1/4-inch rounds
• 1 tablespoon olive oil or avocado oil
• 2 tablespoons butter
• 3 cloves garlic, minced
• 1/2 small yellow onion, finely chopped (optional for stricter keto, but adds flavor)
• 1 cup heavy cream
• 4 ounces cream cheese, softened and cubed
• 1 1/2 cups shredded mozzarella, divided
• 1/2 cup grated Parmesan, divided
• 1 teaspoon Dijon mustard
• 1/2 teaspoon dried thyme or Italian seasoning
• 1/4 teaspoon red pepper flakes (optional)
• Salt and black pepper to taste
• Fresh parsley or chives, chopped, for garnish

Method

 

1. Prep the zucchini: Slice the zucchini into even rounds.

   Spread them on a sheet pan and sprinkle with 1 teaspoon salt. Let them sit for 15 minutes to draw out moisture. Pat dry thoroughly with paper towels.

2. Preheat the oven: Set your oven to 375°F (190°C).

   Lightly grease a 9×13-inch baking dish or similar casserole dish.

3. Sauté the aromatics: Heat the olive oil and butter in a large skillet over medium heat. Add the onion (if using) and cook 3–4 minutes until soft. Stir in the garlic and cook 30 seconds until fragrant.
4. Make the cream sauce: Pour in the heavy cream and add the cream cheese cubes.

   Stir gently until the cream cheese melts and the sauce is smooth, about 3–4 minutes.

5. Season and add cheese: Stir in Dijon, thyme or Italian seasoning, red pepper flakes, a big pinch of pepper, and a pinch of salt. Add 1 cup mozzarella and 1/4 cup Parmesan. Stir until melted and creamy.

   Taste and adjust salt and pepper.

6. Pre-cook the zucchini (quick sauté): In a separate skillet, warm a little oil over medium-high heat. Sauté the zucchini in two batches for 2–3 minutes per side until just tender and lightly browned. Don’t overcook.
7. Assemble the casserole: Layer half the zucchini in the baking dish.

   Spoon over half the cheese sauce. Repeat with remaining zucchini and sauce. Top with the remaining 1/2 cup mozzarella and 1/4 cup Parmesan.

8. Bake: Place the casserole on the center rack and bake for 18–22 minutes, until bubbly around the edges and the top is golden in spots.
9. Rest and garnish: Let it rest 5–10 minutes to set.

   Sprinkle with fresh parsley or chives before serving.

What Makes This Recipe So Good

• Low in carbs, big on flavor: Zucchini keeps the carbs down while a rich cheese sauce delivers that classic casserole satisfaction.
• No soggy vegetables: A quick pre-salt and sauté help remove excess moisture so the casserole bakes up creamy, not watery.
• Simple and flexible: Use what you have—different cheeses, add-ins like cooked bacon or spinach, or a different herb blend.
• Meal-prep friendly: Holds up well in the fridge and reheats without losing texture.
• Family-approved: It tastes indulgent, even for those who aren’t doing keto.

Ingredients

• 3 medium zucchini (about 1.5–2 pounds), sliced into 1/4-inch rounds
• 1 tablespoon olive oil or avocado oil
• 2 tablespoons butter
• 3 cloves garlic, minced
• 1/2 small yellow onion, finely chopped (optional for stricter keto, but adds flavor)
• 1 cup heavy cream
• 4 ounces cream cheese, softened and cubed
• 1 1/2 cups shredded mozzarella, divided
• 1/2 cup grated Parmesan, divided
• 1 teaspoon Dijon mustard
• 1/2 teaspoon dried thyme or Italian seasoning
• 1/4 teaspoon red pepper flakes (optional)
• Salt and black pepper to taste
• Fresh parsley or chives, chopped, for garnish

Step-by-Step Instructions

1. Prep the zucchini: Slice the zucchini into even rounds.

   Spread them on a sheet pan and sprinkle with 1 teaspoon salt. Let them sit for 15 minutes to draw out moisture. Pat dry thoroughly with paper towels.

2. Preheat the oven: Set your oven to 375°F (190°C).

   Lightly grease a 9×13-inch baking dish or similar casserole dish.

3. Sauté the aromatics: Heat the olive oil and butter in a large skillet over medium heat. Add the onion (if using) and cook 3–4 minutes until soft. Stir in the garlic and cook 30 seconds until fragrant.
4. Make the cream sauce: Pour in the heavy cream and add the cream cheese cubes.

   Stir gently until the cream cheese melts and the sauce is smooth, about 3–4 minutes.

5. Season and add cheese: Stir in Dijon, thyme or Italian seasoning, red pepper flakes, a big pinch of pepper, and a pinch of salt. Add 1 cup mozzarella and 1/4 cup Parmesan. Stir until melted and creamy.

   Taste and adjust salt and pepper.

6. Pre-cook the zucchini (quick sauté): In a separate skillet, warm a little oil over medium-high heat. Sauté the zucchini in two batches for 2–3 minutes per side until just tender and lightly browned. Don’t overcook.
7. Assemble the casserole: Layer half the zucchini in the baking dish.

   Spoon over half the cheese sauce. Repeat with remaining zucchini and sauce. Top with the remaining 1/2 cup mozzarella and 1/4 cup Parmesan.

8. Bake: Place the casserole on the center rack and bake for 18–22 minutes, until bubbly around the edges and the top is golden in spots.
9. Rest and garnish: Let it rest 5–10 minutes to set.

   Sprinkle with fresh parsley or chives before serving.

How to Store

• Refrigerator: Cool completely, then cover and refrigerate for up to 4 days.
• Freezer: Freeze in an airtight container for up to 2 months. Thaw overnight in the fridge for best texture.
• Reheating: Warm individual portions in the microwave at 50–70% power to prevent breaking the sauce, or reheat in a 325°F oven, covered, until hot.

Health Benefits

• Low in net carbs: Zucchini is naturally low-carb and fiber-rich, making it a great base for keto meals.
• Good fats for satiety: The cream, cheese, and butter provide fat that helps you feel full and satisfied.
• Micronutrient boost: Zucchini offers vitamin C, potassium, and antioxidants with very few calories.
• Protein support: The cheese adds a moderate amount of protein, helpful for muscle maintenance on a low-carb plan.

What Not to Do

• Don’t skip salting the zucchini: This step helps release moisture. Skipping it can make the casserole watery.
• Don’t overcook the zucchini: It should be just tender before baking; too soft and it can turn mushy.
• Don’t boil the sauce: Keep it at a gentle simmer.

  Boiling can cause the dairy to separate.

• Don’t overload with added veggies: Too many watery vegetables (like tomatoes) can throw off the texture unless pre-roasted.
• Don’t forget to rest: Letting the casserole sit after baking helps the sauce thicken and set.

Variations You Can Try

• Chicken and zucchini bake: Fold in 2 cups cooked, shredded chicken for extra protein.
• Bacon and cheddar: Swap mozzarella for sharp cheddar and stir in 4–6 slices of cooked, crumbled bacon.
• Spinach upgrade: Add 2 cups fresh spinach to the sauce and wilt it down before layering.
• Pesto twist: Stir 2 tablespoons basil pesto into the cream sauce for bright, herby flavor.
• Mushroom lover’s: Sauté 8 ounces sliced mushrooms until browned and add between layers. Drain well first.
• Spicy jalapeño: Add sliced jalapeños and use pepper jack in place of mozzarella for some heat.
• Dairy-light option: Use half heavy cream and half unsweetened almond milk with a little extra cream cheese for thickness.

FAQ

Can I use yellow squash instead of zucchini?

Yes. Yellow squash has a similar texture and moisture level.

Treat it the same way—salt, pat dry, and lightly sauté before assembling.

How do I keep the casserole from getting watery?

Salt and drain the zucchini, pat it dry, and give it a quick sauté to release extra moisture. Also avoid adding raw high-moisture veggies and let the casserole rest after baking.

Is this recipe gluten-free?

It is naturally gluten-free. The sauce thickens from cream cheese and reduced cream, so there’s no flour needed.

What can I use instead of heavy cream?

You can use a mix of unsweetened almond milk and cream cheese to keep it creamy.

Avoid coconut milk unless you like the flavor, as it will change the taste.

Can I make it ahead?

Assemble up to the baking step, cover, and refrigerate for up to 24 hours. When ready, bake straight from the fridge, adding a few extra minutes.

What should I serve it with?

It’s great with a simple green salad, roasted chicken, or grilled sausage. For a vegetarian meal, pair it with a crisp cucumber salad or olives for extra fat and flavor.

How many carbs are in a serving?

Exact numbers depend on brands and portion size, but a typical serving lands around 5–7g net carbs.

Check your labels and calculate for best accuracy.

Can I add eggs to make it more like a frittata?

You can whisk 3–4 eggs into the sauce for a sturdier, brunch-style bake. Reduce the cream slightly so it sets nicely.

Wrapping Up

This Keto Zucchini Casserole is all about simple steps and big payoff. With a few tricks to manage moisture and a creamy, flavorful sauce, you get comfort food that fits your goals.

Keep the base recipe on hand and switch up the add-ins to match your mood or what’s in the fridge. It’s reliable, delicious, and easy enough for any night of the week.