Step 1: Prepare the Meatball Mixture

In a large mixing bowl, combine the ground beef, breadcrumbs, grated Parmesan, chopped parsley, egg, garlic powder, onion powder, salt, and pepper. Use your hands or a wooden spoon to gently mix until all ingredients are evenly incorporated. Avoid overmixing, which can make the meatballs tough.

Step 2: Shape the Meatballs

Using your hands or a small scoop, form the mixture into uniform 1 to 1.5-inch balls. You should get about 18–20 meatballs from one pound of beef.

Step 3: Brown the Meatballs

Heat 1 tablespoon of olive oil in a skillet over medium heat. Add the meatballs in batches and sear them for about 2–3 minutes on each side, until browned. You don’t need to cook them through—just enough to get that rich flavor and help them hold their shape during slow cooking.

Step 4: Prepare the Slow Cooker Gravy

In the bottom of your slow cooker, whisk together the beef broth, onion soup mix, Worcestershire sauce, and cornstarch (if using). Stir in the sliced mushrooms. This mixture will thicken and become the delicious gravy that envelops the meatballs.

Step 5: Add Meatballs to the Slow Cooker

Carefully place the browned meatballs into the slow cooker, nestling them into the gravy and mushrooms. Spoon a bit of gravy over the top so they’re fully coated.

Step 6: Slow Cook to Perfection

Cover and cook on LOW for 4–5 hours or HIGH for 2–3 hours, until the meatballs are cooked through (internal temperature of 160°F) and the gravy has thickened. Give it a gentle stir halfway through if desired.

Step 7: Serve and Enjoy

Serve the meatballs hot, spooning generous amounts of gravy and mushrooms over your favorite sides like mashed potatoes, egg noodles, or rice. Garnish with extra parsley for a fresh finish.