Step 1: Soften the breadcrumbs - In a large bowl, mix the Italian breadcrumbs and milk together. Let them sit for a minute or two until the breadcrumbs soak up the milk and become soft. This little step makes a big difference in keeping the meatloaf tender.
Step 2: Add the seasonings and eggs - Crack the eggs into the bowl and add the Italian seasoning, garlic powder, salt, and black pepper. Stir everything together until it looks well combined and smooth.
Step 3: Gently mix in the ground beef - Add the ground beef to the bowl. Using clean hands or a fork, gently mix everything together just until combined. Do not overwork it. This is where a lot of meatloaves go wrong. Gentle mixing keeps it tender.
Step 4: Shape the meatloaf and place in the slow cooker - Line your slow cooker with a piece of foil, leaving a little extra hanging over the sides so you can lift the meatloaf out later. Shape the meat mixture into a loaf and set it right on the foil in the slow cooker.
Step 5: Spoon marinara over the top - Spread the marinara sauce evenly over the top of the meatloaf. This keeps it moist as it cooks and gives it that cozy Italian flavor right from the start.
Step 6: Cook low and slow - Cover and cook on low for 5 to 6 hours. Try not to peek too much. Let the slow cooker do its thing.
Step 7: Add the cheese - About 10 to 15 minutes before serving, sprinkle the shredded mozzarella over the top of the meatloaf. Cover again and let the cheese melt into a bubbly, cheesy layer.
Step 8: Rest before slicing - Once cooked, let the meatloaf rest for about 10 minutes before slicing. This helps it hold together and gives you those clean, beautiful slices.