Preheat the oven to 375 degrees F with the rack in the middle. Spray a 13″ X 9″ casserole dish with cooking spray.

Thaw spinach & press out any water. In a bowl combine the spinach, ricotta cheese, cottage cheese & parsley. Season with some salt & pepper. Set aside.

Add oil to a medium sized sauté pan. Sauté the onion & garlic in a pan over medium heat for about 5 minutes, until softened & fragrant. Add this to the cheese mixture. Combine well.

Assemble the lasagna: Pour 1/2 of the jarred sauce into the pan. Layer on 5 noodles. Top with 1/2 of the cheese & spinach mixture. Repeat this: sauce, noodles, cheese. Top with another layer of 5 noodles. Top with the additional 1 cup of sauce & the mozzarella cheese.

Cover the lasagna in foil & bake for 20 minutes. Uncover & broil on low for 5 minutes. Cheese should be browned & bubbly.

Serve hot. This makes great leftovers too! Just let it cool, then store in an airtight container for about 3 days in the fridge.