To make lasagna in a slow cooker, first cook the ground beef and seasoning in a large non-stick skillet over medium-high heat until the beef is browned, stirring to crumble. Drain and set it aside. Ground meat should always be browned and drained before going into the slow cooker. Otherwise, it may clump and add grease to the dish.
Combine the pasta sauce and water in a small bowl and set aside.
Coat the inside of the slow cooker with cooking spray to help prevent the noodles from sticking to the sides of the cooker.
Place 4 uncooked lasagna noodles in the slow cooker, breaking the noodles to fit.
Layer with one-half each of the beef mixture, the pasta sauce mixture, and the mushrooms. Spread ricotta cheese over the mushrooms. , and Sprinkle sprinkle with 1 cup of mozzarella cheese.
Layer with the remaining noodles, meat, pasta sauce mixture, and mushrooms. Sprinkle with the remaining 1/2 cup mozzarella cheese.
Cover and cook on HIGH for 1 hour.
Then, reduce heat to LOW and cook 4 hours.