Brown the ground beef in a large skillet over medium high heat and drain the excess grease.
Add the ground beef into the slow cooker.
Add diced onion and red bell pepper into the slow cooker.
Pour in the crushed tomatoes and diced tomatoes.
Add in seasonings.
Pour in the beef broth and then mix to combine ingredients.
Cook on LOW for 6-8 hours or HIGH for 3-4 hours.
Break lasagna noodles into small pieces and stir them in.
Cook for an additional 30 minutes on high, or until the noodles are cooked through.
Serve and top with ricotta and mozzarella.
Notes
Lasagna noodles can be hard to break by hand. It might be helpful to put them into a bag and hit them with a rolling pin to break them up. Or, you can use a different type of noodle.
I usually put the lasagna noodles in at the 3-hour mark and then let it cook for an additional 30 minutes.