Easy Low Carb Keto Pizza Casserole

The smell of Italian sausage browning in a cast iron skillet always pulls my husband into the kitchen, asking what's for dinner. This pizza casserole started as a desperate weeknight invention when I was craving comfort food but watching my carbs. Now it's the most requested meal in our house, even from the carb-lovers.

Last month my sister-in-law stayed over and I threw this together while we caught up. She took three helpings and finally asked where the crust was, completely baffled that she'd been eating what she called 'diet food' the whole time. That's when I knew this recipe was a keeper.

Ingredients

• 1 lb ground Italian sausage: The fennel and herbs in the sausage are what really sell the pizza flavor, so don't skip this
• 20 slices pepperoni: These crisp up beautifully on top and add that classic pizza finish
• 1 cup sliced mushrooms: They shrink down and become little flavor bombs soaking up all the Italian seasonings
• 1/2 cup diced green bell pepper: Adds that fresh crunch and sweetness you expect on a good pie
• 1/2 cup diced onion: Sweetens as it cooks and provides that aromatic base
• 2 cloves garlic, minced: Don't be shy with fresh garlic, it makes the whole kitchen smell amazing
• 1 cup sugar-free pizza sauce: Read labels carefully here, some 'sugar-free' sauces still have surprising amounts of hidden carbs
• 2 cups shredded mozzarella: The cheese that pulls and stretches just like real pizza
• 1/2 cup shredded cheddar: Adds a sharp bite that cuts through the rich sausage
• 1/4 cup grated Parmesan: Sprinkle this on last for that salty, umami finish
• 1 tsp dried Italian herbs: If you have fresh oregano and basil growing, use double this amount
• 1/2 tsp salt and black pepper: The cheese and sausage are already salty, so taste before adding more
• Red pepper flakes: Just enough to wake up your palate without overwhelming everything else

Instructions

Get your oven ready:

Preheat to 400°F and let it come to full temperature while you work, ensuring that cheese melts evenly

Brown your sausage to perfection:

Cook the Italian sausage in a large skillet over medium heat until it's deeply browned and fragrant, then drain any excess fat that pools

Build the vegetable base:

Add the mushrooms, bell pepper, onion, and garlic to the skillet, sautéing for 3-4 minutes until they've softened and released some moisture

Bring everything together:

Pour in the pizza sauce with the Italian herbs, salt, and pepper, letting it simmer for just 2-3 minutes so the flavors marry

Assemble your casserole:

Transfer the sausage and vegetable mixture into a greased 9x9 baking dish, spreading it into an even layer

Layer on the cheesy goodness:

Sprinkle the mozzarella and cheddar across the top, followed by the Parmesan, and arrange those pepperoni slices like little pepperoni-topped islands

Bake until bubbly:

Pop it in the oven for 20-25 minutes, watching for that golden cheese and the edges to start bubbling up

Practice the hardest step:

Let it rest for 5 minutes before serving, giving the cheese time to set so you get actual servings instead of a delicious mess

Save

This recipe has become my go-to for new parents and friends recovering from surgery, since it reheats beautifully and feels indulgent while actually being pretty nutritious. There's something about pizza flavors that just makes everything better.

Make It Your Own

Switch out the sausage for ground beef or turkey if you're watching your saturated fat, though you might need to bump up the Italian herbs to compensate for lost flavor. Plant-based crumbles work surprisingly well here too.

Double It for Meal Prep

This casserole freezes beautifully, so I always make two when I have the oven on. Portion it into individual containers before freezing for those nights when cooking feels impossible.

Serving Suggestions That Pull It Together

A crisp green salad with a sharp vinaigrette cuts through all that rich cheese, and don't knock it until you try it, but some sautéed broccoli rabe on the side makes this feel like an Italian Sunday dinner.

• Warm your plates before serving to keep the cheese melty longer
• Extra red pepper flakes on the table lets everyone control their heat level
• Leftovers reheat beautifully at 350°F for about 15 minutes

Save

There you have it, pizza night without the guilt or the carb coma. Now go preheat that oven and get ready to make some magic.

Recipe Questions

→ Can I freeze this casserole?

Yes, assemble and bake completely, then cool and freeze in portions for up to 3 months. Reheat in the microwave or oven at 350°F until warmed through.

→ What vegetables work best?

Mushrooms, bell peppers, and onions complement the Italian flavors beautifully. You can also add spinach, black olives, or roasted red peppers for variety.

→ Can I make it spicy?

Absolutely! Add red pepper flakes to the meat mixture or use spicy Italian sausage. You can also arrange sliced jalapeños on top before baking.

→ How do I store leftovers?

Store in an airtight container in the refrigerator for up to 4 days. The flavors actually develop more depth overnight, making it excellent for meal prep.

→ Can I use different meats?

Ground beef, turkey, or plant-based crumbles work well. For a vegetarian version, skip the meat entirely and add more vegetables like zucchini or eggplant.