Add the olive oil to a very large skillet or Dutch oven over medium heat.
1 tbsp olive oil
Once heated, add the sausage and use a wooden spoon to break it up into chunks. Brown the sausage and drain any fat that remains in the pan.
1 lb. Italian sausage
Add in the onion, garlic, and Italian seasoning, sautéing until the onions are soft.
½ onion, 3 cloves garlic, 1 tsp Italian seasoning
Pour the marinara sauce and broth over the meat and stir until combined.
36 oz. marinara sauce, 1½ cups low-sodium beef broth
Spray the crockpot with nonstick cooking spray.
Spread a layer of meat sauce in the bottom of the slow cooker covering it completely.
Top with half of the uncooked pasta.
1 lb. dry ziti pasta
Drop 4-5 spoonfuls of ricotta over pasta.
1 cup ricotta cheese
Sprinkle ½ cup mozzarella cheese over the ricotta.
2 cups mozzarella cheese
Repeat with another layer of meat sauce, the remaining pasta, the remaining ricotta, and ½ cup mozzarella. Spread the remaining meat sauce over the top.
Cover and cook on high for 1½-2 hours or on low for 2-4 hours. At the lower end of the cook time, check to make sure the pasta isn't getting mushy.
Top with remaining mozzarella cheese.
Serve with grated Parmesan and fresh basil, if desired.
grated Parmesan cheese, fresh basil