Preparation Steps

• Heat olive oil in a skillet over medium heat. Add chopped onion and cook until softened, about 3 to 4 minutes. Add minced garlic and cook 30 seconds more.
• Add ground beef to the skillet and cook until browned, breaking it up with a spoon. Drain excess fat if necessary, then stir in Italian seasoning, salt, and pepper.
• Stir the marinara sauce into the cooked beef mixture and simmer 2 to 3 minutes to combine flavors. Remove from heat.
• In a large bowl, combine ricotta, 2 cups of mozzarella, and grated Parmesan. Season with a pinch of salt and pepper and mix until smooth.
• Spray the slow cooker insert with nonstick spray. Spread a thin layer of the meat and sauce mixture on the bottom. Add a layer of uncooked ziti, breaking pieces if needed to fit.
• Spoon half of the ricotta-cheese mixture over the pasta, then add another layer of sauce and pasta. Pour the remaining water evenly over the layers to help the pasta soften.
• Top with the remaining sauce and mozzarella (reserve 1 cup to add near the end if desired). Cover and cook on HIGH for 3 to 4 hours or on LOW for 6 to 8 hours, until pasta is tender.
• If you reserved extra cheese for a melty top, sprinkle the reserved mozzarella over the ziti during the last 10 to 15 minutes of cooking with the lid off to melt and brown slightly.
• Turn off the slow cooker and let the baked ziti rest 10 minutes before serving. Garnish with chopped fresh basil and additional Parmesan if desired.