If there is one thing I know I can make that the kids will devour with no complaints, it is definitely these Amazing Mega Stuffed Meatballs with Tomato Sauce. Big, juicy beef meatballs packed with oozy melted mozzarella, sweet peppers and onion make every bite so delicious.

What's not to love, right? They always remind me of pizza stuffed meatballs, with all those favourite pizza flavours we love, served in a rich tomato sauce. Tender beef, gooey cheese and tasty veg make these a family favourite every single time.
Calories in Mega Stuffed Meatballs
This recipe serves 4 and is 398 calories per serving.
If you're looking for more recipes by calories, you'll find plenty of options grouped by calorie range here: Slimming Eats Low Calorie Recipes
If you're following a calorie-controlled diet or a healthy eating plan, it's important to calculate your daily calorie needs using a reliable calorie calculator. The calorie counts provided are estimates and can vary depending on the exact ingredients and portion sizes you use. Using your own calculations helps ensure you're meeting your individual needs. A calorie calculator can help you make informed choices and stay on track with your goals.
See the recipe card for full nutritional estimation.

Ingredient Notes
To make this recipe you will need the following ingredients:
- Extra Lean Ground beef: I like to use extra lean ground beef for the meatballs, as it keeps them juicy and flavourful without becoming too greasy.
- Breadcrumbs: These help bind the meatball mixture together and keep the texture nice and tender.
- Egg: The egg helps hold everything together so the meatballs keep their shape as they cook.
- Milk: A little milk keeps the meatballs soft and moist, giving them a more tender texture.
- Seasonings: The Italian seasoning, garlic powder and salt add flavour to the meatball mixture, while the paprika, salt and black pepper season the filling and give it extra depth.
- Mozzarella: Mozzarella gives that delicious oozy melted centre, which makes these meatballs extra special. Use fresh mozzarella torn into equal sized pieces so you can easily stuff the meatballs
- Onion and bell peppers: The onion and bell peppers are part of the filling and add sweetness, colour and extra flavour, giving these stuffed meatballs that delicious pizza-style taste.
- Chopped tomatoes: These form the base of the sauce and give it a rich tomato flavour. Make sure you use a good quality brand in a rich tomato sauce to ensure the best result. Mutti is my favourite brand.
- Chicken Stock: Stock adds extra depth to the sauce and helps create the perfect consistency for simmering the meatballs. I use better than bouillon paste
- Tomato paste: This gives the sauce a deeper, richer tomato flavour and helps thicken it slightly.
- Garlic: Fresh garlic adds lots of savoury flavour to the sauce and works really well with the beef and tomatoes.
- Balsamic vinegar: Just a splash adds a slight sweetness and depth that really lifts the tomato sauce.
- Sugar: A little sugar helps balance the acidity of the tomatoes. You can use granulated sweetener if you prefer.
Once you've gathered all the ingredients and prepared them accordingly, you're all set to create this easy and delightful recipe.
See the recipe card for specific quantities and instructions.
Variations and Substitutes
These stuffed meatballs are really easy to adapt depending on what you have on hand. You can swap the ground beef for pork, chicken or turkey, or even use a half beef, half pork mix for extra flavour and tenderness. If you want to keep the filling more simple, just use the mozzarella on its own without the onion and pepper mixture and they will still be absolutely delicious. You can also switch the mozzarella for another cheese like cheddar, Monterey Jack or provolone, although mozzarella will give you the best oozy melted centre.
For the sauce, there are lots of easy ways to change up the flavour. If you like a bit of heat, add some chilli flakes, harissa or a pinch of cayenne. A spoonful of red pesto is great for extra depth, and chopped sundried tomatoes work really well stirred into the sauce too. For a richer sauce, you can stir in a little light cream cheese or a splash of cream at the end, which is a really nice twist. You can also add a little smoked paprika, fresh basil or even finely diced mushrooms or onion to bulk the sauce out a little more and add extra flavour.

Tips for making stuffed meatballs
- Seal the meatballs really well
Make sure the filling is completely enclosed in the meat mixture with no gaps or cracks. If there are any thin spots, the cheese is much more likely to ooze out as they cook. - Do not overfill
It can be tempting to add lots of mozzarella, but too much filling makes them harder to seal properly. A small cube or little pile in the centre is enough to get that lovely oozy middle. - Flatten then wrap
I find it easiest to flatten the meat mixture in your hand, add the filling to the middle, then gently bring the meat up and around it. Roll carefully between your hands to seal it fully. - Bake first to help them hold their shape
Baking the meatballs in the oven first helps them firm up and seal before they go into the sauce, which is a great way to stop too much filling escaping. - Chill before baking if needed
If the meatballs feel very soft after shaping, pop them in the fridge for a little while before baking. This can help them hold together better. - Use a gentle simmer in the sauce
Once added to the sauce, keep it at a gentle simmer rather than a rapid boil. If the sauce is bubbling too aggressively, the meatballs are more likely to split and lose some of the filling. - A little cheese escaping is normal
Don't worry if a tiny bit of cheese escapes, that often happens with stuffed meatballs. As long as most of the filling stays inside, they will still be absolutely delicious.
Side Suggestions
These stuffed meatballs are really versatile, so you can serve them with all kinds of sides depending on what you are in the mood for. They are great with pasta, rice (like this herby garlic rice, mashed potatoes or garlic and herb roasted potatoes if you want something extra comforting, and a big spoonful of the tomato sauce over everything is always a must.
To balance out the richness of the meatballs and melted cheese, I like to add something lighter alongside, like a simple salad or some green vegetables. A crisp mixed salad, steamed broccoli,Roasted garlic french green beans or even some sautéed or roasted courgette all work really well. It just helps round out the meal nicely and makes it feel like a proper family dinner.

Storing, Freezing and Reheating
Storing :These stuffed meatballs store really well, so they are great for leftovers. Once cooled, keep them in an airtight container in the fridge for up to 3 days. Store them with the sauce to help keep them nice and juicy.
Freezing: You can freeze these too, either with or without the sauce, although I prefer freezing them in the sauce so they stay moist when reheated. Allow everything to cool completely first, then freeze in a suitable container for up to 3 months. Defrost overnight in the fridge before reheating.
Reheating :Reheat in a pan on the stovetop over a low to medium heat until the meatballs and sauce are piping hot right through. You can also reheat them in the microwave if that is easier. If the sauce has thickened too much, just add a splash of stock or water to loosen it up.
More Meatballs Recipes
Love meatballs? Check out some of these other recipes:
- Pork Meatballs with Spicy Pineapple Sauce
- Teriyaki Meatballs
- Apricot Chicken Meatballs
- Vegetarian Meatballs in Creamy Tomato Sauce
- Chicken Quinoa Meatballs in a Veggie Sauce
- Swedish Meatballs and Gravy
- Pork and Sweet Potato Meatballs
- Chicken and Mango Meatballs with a Spicy Mango Sauce
- Moussaka Meatballs
- Asian Chicken Meatballs
- Spaghetti and Meatballs
- Lamb Meatballs with a Spicy Tomato Sauce
or if you would like more recipe ideas - head on over to the FULL RECIPE INDEX where you will find over 900 delicious recipes with calories and you can search by meal type, ingredients, course, diet and more.
All recipes on Slimming Eats have estimated nutritional information for your convenience.

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Danielle browne says
Delicious! ! Had these the other week. My husband and son loved them too......that's why we're having them again tomorrow! ! 🙂 thanks for sharing x
Caroline says
Hi - I'm looking forward to making these! What are Italian breadcrumbs..... I'm in the UK and not sure whether to use panko/fresh breadcrumbs/dried breadcrumbs?
Thank you!!
Shevy (Slimming Eats) says
dried or fresh breadcrumbs should be fine (not panko). Just adjust syns to the ones you use as they may vary.
Mia says
Omg I made these tonight and wow this dinner has become my new fav and I will definitely be making them again
Amanda says
Can you use dried parsley and basil instead of fresh please
Siobhan (Slimming Eats) says
yes dried is fine to use if you don't have fresh.
Michelle says
Could I make these spicy meatballs?
Siobhan (Slimming Eats) says
yep you sure can, add some red chilli flakes or a pinch of cayenne for some heat.
Maria Bland says
Wow Siobhan these meatballs are divine as is the sauce - I took your advice and used Mutti for the tin tomatoes - thank you for another fantastic recipe