Low Carb Keto Crustless Pizza Casserole

The first time I made this, my skeptical husband took three helpings and then asked when we were having it again. Something about bubbling cheese and pepperoni makes everyone instantly happy, regardless of the missing crust.

Last winter when my sister was doing keto, I served this at a family dinner and watched her eyes light up at having something actually indulgent on her plate. That moment of watching someone feel included in the comfort food fun stuck with me.

Ingredients

• Ground Italian sausage: The fennel and herbs here do heavy lifting for flavor, but beef or turkey work if you need something milder
• Mushrooms: They shrink down and get all meaty, adding umami without many carbs
• Green bell pepper and onion: These give you those classic pizza toppings that cook into sweet savory bits
• Garlic: Do not skip this, even if you think two cloves seems like a lot
• Sugar-free pizza sauce: Check labels carefully because regular pizza sauce sneaks in shocking amounts of sugar
• Mozzarella cheese: Shred it yourself if you can, it melts so much better than the pre-shredded stuff with anti-caking agents
• Cheddar cheese: Adds a sharper bite that cuts through all the mild mozzarella
• Parmesan cheese: This creates that gorgeous golden crust on top that everyone fights over
• Italian herbs: If you have fresh oregano and basil, use them, but the dried blend works perfectly
• Salt and black pepper: The sausage brings salt already, so taste before adding too much more
• Red pepper flakes: Even a tiny pinch wakes everything up if you like things with a little heat

Instructions

Brown the sausage:

Cook the Italian sausage in a large skillet over medium heat until it is no longer pink, breaking it up with your spoon as it cooks. Drain any excess fat if there is a lot pooling in the pan.

Soften the vegetables:

Toss in the mushrooms, bell pepper, onion, and minced garlic and cook everything for about 4 minutes. You want the vegetables to start releasing their moisture and getting fragrant.

Build the flavor base:

Pour in the pizza sauce and add the Italian herbs, salt, pepper, and red pepper flakes if using. Let this simmer together for 2 or 3 minutes so the flavors really meld.

Assemble the casserole:

Transfer the meat and vegetable mixture into a greased 9x9-inch baking dish and spread it evenly. Scatter the mozzarella and cheddar all over the top, then finish with the Parmesan and pepperoni slices if you are using them.

Melt and bubble:

Bake at 400°F for 20 to 25 minutes until the cheese is completely melted and starting to turn golden brown in spots. The edges should be bubbling enthusiastically.

Rest before serving:

Let the casserole sit for 5 minutes before you dig in. This feels like forever when it smells this good, but it helps the cheese set so you get neat scoops instead of a runny mess.

Save

My daughter now requests this for her birthday dinner every year instead of actual pizza, which says everything about how good it tastes. It became our Friday night tradition during busy sports seasons when we needed something fast but comforting.

Make It Your Own

Sometimes I throw in black olives or spinach when I need to sneak in more vegetables. The beauty of this dish is that it works with whatever pizza toppings your family already loves.

Meal Prep Magic

This actually tastes better on day two after the flavors have had time to hang out together. I make a double batch on Sunday and portion it into containers for the easiest work lunches ever.

Serving Suggestions

A crisp green salad with a simple vinaigrette cuts through all that rich cheese perfectly. If you are not strictly low carb, garlic bread on the side makes everyone happy.

• Warm plates make the cheese stay melty longer
• Extra red pepper flakes on the table lets people heat up their own portions
• Leftovers reheat beautifully in the microwave or oven

Save

There is something so satisfying about watching everyone gather around the table for this cheesy, comforting meal. Hope it becomes a regular in your rotation too.

Questions & Answers

→ Can I use different meats?

Yes, ground beef, turkey, or plant-based crumbles work well as substitutes for Italian sausage. Adjust seasonings to taste.

→ How long does this keep in the refrigerator?

Store in an airtight container for up to 4-5 days. Reheat in the microwave or oven until warmed through.

→ Can I freeze this casserole?

Absolutely! Freeze before baking for up to 3 months. Thaw overnight in the refrigerator, then bake as directed.

→ What vegetables work best?

Mushrooms, bell peppers, and onions provide classic pizza flavors. You can also add black olives, spinach, or roasted red peppers.

→ Is the sugar-free pizza sauce necessary?

For keeping it keto and low-carb, yes. Regular pizza sauce typically contains added sugars. Look for marinara or make your own.

→ Can I make this spicy?

Add red pepper flakes to the meat mixture or use hot Italian sausage. Extra pepperoni also adds a nice kick of heat.