Slow Cooker Meatball Subs

These slow cooker meatball subs are one of the easiest dinners you can make. You just prep the meatballs, drop them in the slow cooker with marinara sauce, and let them cook low and slow until they’re perfectly tender.

The meatballs are made with a mix of ground beef and Italian sausage, which gives them so much more flavor than using just one type of meat.

Once they’re done, you load them into toasted sub rolls, spoon some extra sauce on top, and melt mozzarella cheese under the broiler. It takes just a couple of minutes to pull everything together at the end.

This is a great recipe for busy days when you want something really satisfying but don’t want to spend a lot of time in the kitchen.

It also works well for feeding a group since it makes about 6 loaded subs. Let’s get into it!

What Makes This Recipe So Good

The Beef and Italian Sausage Combo Is a Game Changer – Mixing ground beef with Italian sausage gives these meatballs way more flavor and juiciness than using beef alone, and that rich, savory taste soaks into the marinara as it slow cooks for hours.

Hands-Off Cooking That Actually Builds Flavor – After about 15 minutes of mixing and rolling the meatballs, your slow cooker does all the heavy lifting while the meatballs slowly braise in marinara, getting incredibly tender and packed with sauce flavor in a way that oven-baked meatballs just can’t match.

Perfect for Feeding a Crowd – This recipe makes about 20 meatballs and fills 6 loaded subs, making it an awesome choice for game day, a casual dinner party, or feeding a hungry family without needing to stand over the stove all day.

Ingredients

For the Meatballs

• 1 lb Ground Beef
• 1/2 lb Ground Italian Sausage
• 1/3 cup Italian Breadcrumbs
• 1/4 cup Grated Parmesan Cheese
• 1 large Egg
• 3 cloves Garlic, minced
• 1 tsp Italian Seasoning
• 1/2 tsp Salt
• 1/4 tsp Black Pepper

For the Sauce & Assembly

• 24 oz Marinara Sauce (1 jar)
• 1/4 tsp Red Pepper Flakes
• 6 Sub Rolls, split and toasted
• 1.5 cups Shredded Mozzarella Cheese
• Fresh Basil Leaves, for garnish

Directions

Step 1

In a large bowl, combine the ground beef, ground italian sausage, italian breadcrumbs, grated parmesan, egg, minced garlic, italian seasoning, salt, and black pepper. Mix gently until just combined. Roll the mixture into about 20 meatballs, roughly 1.5 inches each.

Step 2

Pour about half of the marinara sauce into the bottom of the slow cooker. Arrange the meatballs in a single layer on top of the sauce.

Step 3

Pour the remaining marinara sauce over the meatballs and sprinkle with red pepper flakes.

Step 4

Cover and cook on low for 6 to 7 hours or on high for 3 to 4 hours, until the meatballs are cooked through and tender.

Step 5

Load 3 to 4 meatballs into each toasted sub roll and spoon extra marinara sauce from the slow cooker over the top.

Step 6

Top each sub with a generous handful of shredded mozzarella cheese. Place under the broiler for 1 to 2 minutes until the cheese is melted and bubbly.

Step 7

Garnish with fresh basil leaves and serve hot.

Pro Tips

Don’t Overmix the Meat

When you’re combining the beef, sausage, breadcrumbs, and everything else, use your hands and mix just until the ingredients are evenly distributed. You want to stop as soon as you don’t see any pockets of plain meat or dry breadcrumbs.

Overmixing compresses the proteins and makes meatballs dense and rubbery instead of tender. Think of it like gently folding things together rather than kneading it like dough.

Wet your hands with a little cold water before rolling the meatballs. This keeps the meat from sticking to your palms and makes it way easier to shape them evenly.

Brown the Meatballs Before the Slow Cooker

The recipe doesn’t call for it, but searing the meatballs in a hot skillet for about 2 minutes per side before adding them to the slow cooker makes a big difference. You get a nice browned crust that adds flavor you just can’t get from slow cooking alone.

You don’t need to cook them through – just get some color on the outside. Use a tablespoon of oil in a skillet over medium-high heat and work in batches so they aren’t crowded.

This also helps the meatballs hold their shape better during the long cook. Without searing, they can sometimes get a little mushy or start to break apart in the sauce.

Keep the Meatballs the Same Size

Try to keep all your meatballs as close to 1.5 inches as possible. If some are big and some are small, the small ones will overcook and dry out while the big ones are still catching up.

A good trick is to use a cookie scoop or a tablespoon measure so each one gets the same amount of meat. About 1.5 tablespoons of the mixture per meatball gets you right in that 1.5 inch range.

Related Recipes

• Instant Pot Chili
• Instant Pot Birria Tacos
• Instant Pot Mississippi Pot Roast
• Instant Pot Beef Stew
• Instant Pot Salsa Chicken

Frequently Asked Questions

Can I use all ground beef instead of mixing it with Italian sausage?

You can, but the Italian sausage is what gives these meatballs a lot of their flavor and juiciness. If you use all ground beef, the meatballs will still work but they might taste a bit more plain.

If you go with all beef, try adding an extra half teaspoon of Italian seasoning and a pinch of fennel seed to make up for the flavor you’re losing from the sausage.