One-Skillet Low Carb Hamburger Casserole

This low carb hamburger casserole cooks in a single skillet and bakes up with a rich, meaty sauce and a golden layer of melted cheese. It’s the kind of dinner that feels hearty without loading up on carbs.

You only need one pan, a few simple ingredients, and about 35 minutes to get it on the table. No fussy steps, just straight forward comfort food that keeps you full.

Why This Casserole Works

Browned ground beef gives the sauce a deep, savory backbone, while peppers and zucchini keep each bite tender without adding starchy filler. A blanket of melted cheddar on top makes it feel indulgent, but the whole thing stays under 10 grams of net carbs per serving.

It reheats beautifully, too. I often make it on Sunday so I have easy lunches ready for the week. The sauce thickens overnight, so the slices hold together even better the next day.

Ingredients

• 1 lb ground beef: 80/20 keeps it juicy without being greasy, leaner blends work but you may need a splash of oil.
• 1 small yellow onion, diced: adds sweetness and depth.
• 1 red bell pepper, diced: any color works, red is the sweetest.
• 2 cloves garlic, minced: fresh gives the best punch.
• 1 medium zucchini, diced: pat it dry after dicing to avoid excess water in the bake.
• 1 (14 oz) can diced tomatoes, undrained: look for no-salt-added if you want to control the sodium yourself.
• 2 tbsp tomato paste: deepens the tomato flavor without more liquid.
• 2 oz cream cheese, cubed: full-fat makes the sauce creamy and helps it cling to the meat and veggies.
• 1 tsp dried oregano
• 1/2 tsp salt, plus more to taste
• 1/4 tsp black pepper
• 1 1/2 cups shredded sharp cheddar cheese: sharp gives more flavor per bite than mild.

Variations and Swaps

• Use ground turkey: turkey stays lean. Brown it the same way, draining any excess fat if needed.
• Dairy-free: swap the cream cheese for a thick canned coconut cream (just the solid part) and use your favorite dairy-free shredded cheddar. The sauce will be slightly looser but still creamy.
• Add more vegetables: sliced mushrooms or a handful of baby spinach stirred in with the zucchini work well.
• Spice it up: add 1/2 tsp red pepper flakes with the garlic, or toss in a seeded jalapeño with the peppers.

Low Carb Cheeseburger Soup is a cozy soup to serve with this casserole.

How to Make Low Carb Hamburger Casserole

Step 1: Brown the Beef and Aromatics

Heat your oven to 400°F (200°C). Set a 12-inch oven-safe skillet over medium-high heat and crumble in the 1 lb ground beef. Cook, breaking it up with a spoon, for about 5 minutes until no pink remains. Toss in the diced onion and bell pepper and cook 3 more minutes, just until they start to soften.

The beef will release its juices. If there’s more than a tablespoon of fat in the pan, spoon off the excess. You want enough to keep things moist but not a pool of grease.

Step 2: Simmer the Sauce

Once the vegetables have softened, stir in the 2 minced garlic cloves and cook for 30 seconds. Add the 2 tbsp tomato paste and stir it through the meat, letting it cook for 1 minute to take the raw edge off. Pour in the undrained can of diced tomatoes, then drop in the 2 oz cream cheese cubes. Sprinkle on the 1 tsp oregano, 1/2 tsp salt, and 1/4 tsp pepper. Simmer the sauce over medium heat for about 5 minutes, stirring now and then until the cream cheese melts and everything turns into a thick, glossy sauce.

You’ll smell the oregano and tomato really coming together here. The sauce should coat the back of a spoon and hold a trail when you drag your finger through it.

Step 3: Layer and Bake the Casserole

Take the skillet off the heat. Fold in the diced zucchini gently, then use your spoon to smooth the top into an even layer. Scatter the 1 1/2 cups shredded cheddar cheese over the whole surface, right up to the edges. Slide the skillet into the hot oven and bake for 15 minutes. The casserole is ready when the cheese is completely melted and bubbling around the rim.

The zucchini will soften but still have a little bite, which keeps the casserole from feeling one-note. If you prefer it softer, you can sauté the dice in a dry pan for a few minutes before adding them.

Step 4: Broil and Serve

Switch the oven to broil on high. Broil the casserole for 1 to 2 minutes, keeping a close eye on it, until the cheese top gets a few golden brown spots. Pull the skillet out and let it sit for 5 minutes.

This rest helps the slices hold together when you scoop them out. Serve the casserole hot, straight from the skillet, with a big spoon.

A Few Notes Before You Start

• Use an oven-safe skillet.: Cast iron or stainless steel both work, and it saves you from transferring the whole thing to a baking dish.
• Pat the zucchini dry.: After dicing, spread the zucchini on a paper towel and press gently. This keeps extra water from thinning the sauce during baking.
• Don’t skip the broil step.: Those browned spots on the cheese add a nutty, savory layer you can’t get from baking alone.
• Rest it for clean slices.: Let the casserole sit 5 minutes after the broil, then scoop. It will be much easier to portion.

Bake times by skillet material:

Keeping Leftovers Fresh

• Refrigerate: Store any leftovers in an airtight container for up to 4 days. The flavors get even better overnight.
• Reheating: A microwave works fine for a quick lunch. For a crispy top again, warm the portion in a toaster oven or under the broiler for a couple of minutes.

What to Serve With Low Carb Hamburger Casserole

A simple green salad with a lemon vinaigrette cuts right through the richness and adds a fresh crunch on the side. Roasted broccoli tossed with olive oil and a pinch of salt also pairs well, its slightly charred edges echoing the broiled cheese on top.

Frequently Asked Questions

Is this casserole keto-friendly?

Yes. One serving comes out to around 9 grams of total carbs, with 2 grams of fiber, so roughly 7 grams net carbs. It fits easily into a keto day.

Can I freeze it?

You can. Cool the baked casserole completely, then portion it into freezer-safe containers. Freeze for up to 2 months and thaw overnight in the fridge before reheating.

How do I keep it from getting watery?

The biggest helper is patting the zucchini dry before it goes in. Also, don’t skip the simmer step: letting the sauce reduce on the stove thickens it so it won’t thin out in the oven.

What can I use instead of zucchini?

Yellow squash works exactly the same way. If you’re not worried about carbs, a cup of cooked cauliflower rice would be a good swap that won’t release much moisture.

Low Carb Hamburger Casserole Recipe

Print Recipe Pin Recipe

Prep Time 15 minutes mins

Cook Time 22 minutes mins

Total Time 37 minutes mins

Servings: 4 servings

Calories: 450

Ingredients Method Notes

Ingredients

  

• 1 lb ground beef
• 1 small yellow onion, diced
• 1 red bell pepper, diced
• 2 cloves garlic, minced
• 1 medium zucchini, diced
• 1 (14 oz) can diced tomatoes, undrained
• 2 tbsp tomato paste
• 2 oz cream cheese, cubed
• 1 tsp dried oregano
• 1/2 tsp salt
• 1/4 tsp black pepper
• 1 1/2 cups shredded sharp cheddar cheese

Method

 

1. Brown the ground beef in an oven-safe skillet over medium-high heat until no pink remains, about 5 minutes. Add onion and bell pepper and cook 3 minutes, draining excess fat if needed.
2. Stir in garlic and tomato paste, cook 1 minute, then add diced tomatoes, cream cheese, oregano, salt, and pepper. Simmer 5 minutes until sauce thickens.
3. Remove from heat, fold in zucchini, smooth the top, and scatter cheddar over the surface. Bake at 400°F (200°C) for 15 minutes until cheese is melted and bubbly.
4. Broil on high 1 to 2 minutes until cheese gets golden spots, rest 5 minutes, then serve.

Notes

For the creamiest sauce, make sure the cream cheese has come to room temperature before you add it; cold cubes take longer to melt and can leave little lumps. The casserole sets up even firmer after a short rest, so don’t rush to scoop it straight from the oven.