Slow Cooker lasagna

We love lasagna but never have enough time for it to cook in the oven. I modified our favourite recipe and have found this version works well. The best part is that it is ready when we get home from work.
Ingredients

* 1 lb. ground beef
* 1 onion, diced
* 3 garlic cloves, minced
* 1 jar spaghetti sauce or tomato sauce

* 1 package no-cook lasagna noodles
* 2 cups shredded mozzarella cheese
* 1 500ml container ricotta cheese
* 1 egg
* 1/3 cup milk
* 1/2 cup water
* 1/2 cup Parmesan cheese
* Salt
* Pepper

Directions

1. Spray a large skillet with cooking spray. Brown beef, garlic and onion then stir in spaghetti sauce and water (the noodles will absorb some of this liquid during cooking) .
2. In a separate bowl combine ricotta, milk, and egg. Stir until smooth. Add salt and pepper to taste.
3. Oil slow cooker (or use a slow cooker insert bag) and cover bottom of pot with sauce mixture. Cover with a layer of noodles, 1/3 of cheese mixture, 1/4 of meat sauce and top with mozzarella and parmesan cheese. Continue two more layers depending on the size of your pot.
4. Top with remaining meat sauce and sprinkle with cheese.
5. Cook on low for 6 hours or until noodles are cooked and liquid has been absorbed but lasagna is not dry.