In a large skillet, cook ground beef, chopped onion, and minced garlic over medium heat until browned. Drain excess fat.
Stir in tomato sauce, tomato paste, salt, and oregano. Simmer for 5 minutes.
In a mixing bowl, combine mozzarella, cottage cheese, and Parmesan.
Spread a layer of meat sauce at the bottom of the slow cooker. Add a layer of uncooked lasagna noodles, breaking them as needed to fit.
Add a layer of cheese mixture. Repeat layers until all ingredients are used, ending with cheese on top.
Cover and cook on low for 4-5 hours or high for 2-3 hours.
Let it rest for 10 minutes before serving.
Garnish with fresh basil or extra Parmesan if desired. Enjoy!