Add the butter, minced garlic, and diced onion to a large non-stick skillet and cook over medium-high heat until the onion is softened and fragrant. Pour the spinach into the skillet and saute until the spinach becomes wilted, about 1-2 minutes.
Place the heavy cream, milk, Parmesan cheese, ricotta cheese, sea salt, and black pepper into the skillet and combine together with the onion-spinach mixture. Then mix in the shredded rotisserie chicken.
Allow the chicken Alfredo sauce to simmer for 3-5 minutes, then remove from heat.
Ladle a 1/2 cup of Alfredo sauce into the bottom of a 9x13 inch baking dish. Next, add the first layer of cooked lasagna noodles (I used 5 noodles per layer). Pour 1 heaping cup of chicken Alfredo sauce over the noodles, then sprinkle 1 cup of mozzarella cheese over the Alfredo sauce. Repeat in order the noodles, chicken Alfredo sauce, and cheese layers two additional times.
Place foil over the baking dish and bake the lasagna in the preheated oven for 30 minutes.
Once baked, remove the foil and allow the cheese to broil in the oven for an additional 2-3 minutes. Serve warm!
Notes
Serve the lasagna alongside fresh vegetables, tossed salad, or chopped fruit to offset the richness of the dish.Cover leftovers with foil and store in the refrigerator for 3-5 days.To freeze cooked lasagna, allow the dish to cool completely on the counter. Then, cover the lasagna with foil, write the date, and place the baking dish in the freezer. It will stay good for 2-3 months.To reheat, cook in the oven at 350 degrees Fahrenheit for 2 hours.