Preheat the oven at 175 °C while cooking the pasta as instructed on the package.
Melt the butter at low heat in a big pan. Add the garlic and cook for 1 minute. Then, add the flour and cook for another minute.
Pour the milk and season with salt and pepper. Turn up the heat and cook for 20 minutes until the mix thickens. Add the parmesan and mix until it thickens a bit more.
Add in the chicken, spinach, and artichoke. Mix it well.
Take a big casserole and place a layer of the chicken mix, then cover it with a layer of pasta, and then with a layer of ricotta. Repeat all the layers until the ingredients run out and finish with a layer of mozzarella.
Cover the casserole with aluminum foil and bake for 40 minutes. Remove the aluminum foil and bake for another 10 minutes to brown the mozzarella.