In a large skillet over medium heat, cook the ground beef or Italian sausage until fully browned. Drain any excess fat.
Add the cooked meat to your slow cooker. Pour in the marinara sauce and crushed tomatoes. Sprinkle with Italian seasoning, salt, and pepper, then stir to combine.
Add the uncooked ziti pasta directly into the slow cooker, stirring well to coat the pasta evenly with the sauce.
Drop spoonfuls of ricotta cheese over the top of the pasta mixture, spreading them slightly with the back of a spoon.
Cover the slow cooker and cook on LOW for 3–4 hours, or until the pasta is tender and cooked through.
About 20 minutes before serving, sprinkle the mozzarella and Parmesan cheeses evenly over the top. Cover again and allow the cheese to melt into a bubbly, golden topping.
Serve hot, garnished with fresh basil if desired, and enjoy a comforting, cheesy, and flavorful baked ziti.
Enjoy!