Preheat oven – Turn the heat up to 425F degrees so that the oven has time to heat up while you prepare the rest of the dish.
Cook Pasta – Cook the pasta in a large pot of salted water according to the package directions. Be sure to reserve some pasta water as the pasta nears its cooking time.
Mix the ground chicken with spices – In a large bowl, mix the ground chicken with salt, fennel, pepper, and paprika. I would recommend using 1.5% grams of the weight of the chicken in salt for ample flavor, which is especially important since we don’t have the fat to rely on to give us flavor here. Mix everything together thoroughly.
Sauté garlic and onions – Mince the garlic and onions into small pieces. Spray a skillet with cooking spray, and turn the stove to medium heat. Sauté the garlic and onions, along with Calabrian chili if using, for about 1-2 minutes or until the aromatics are fragrant.
Cook the chicken – Add the chicken into the pan and cook for about 3-4 minutes.
Mix with tomato sauce and thyme – Add the tomato sauce and thyme and cook for about 2-3 minutes, or until the chicken is thoroughly cooked.
Prepare the casserole – Pour the pasta mixture into a casserole dish if using. If you are using a pan that can be put in the oven, you can also bake it in the pan itself.
Top with cheese and bake – Create little pockets in the pasta and add in the ricotta cheese. Then top with mozzarella. Pockets need to be created for the ricotta, but not for the mozzarella since mozzarella will melt into place. Bake the pasta for about 10 minutes, or until the cheese has fully melted.
Serve and garnish – Top with garnishes, such as fresh basil and red pepper flakes, and enjoy the easiest-to-make lasagna ever!