Preheat your oven to 400°F (200°C) and prepare a 9x13-inch baking dish.

In a large pot, bring salted water to a rolling boil and cook pasta for about 2 minutes less than al dente.

Heat olive oil in a large skillet over medium-high heat, season chicken, and cook until golden brown.

In the same skillet, melt butter and add minced garlic, cook, then add heavy cream and milk and simmer.

Combine cooked pasta and chicken with the sauce, adding baby spinach if desired.

Spread the mixture into the baking dish and top with mozzarella and Parmesan cheese.

Bake uncovered for 20-25 minutes until cheese is melted and slightly browned.

Let the dish rest for about 5 minutes before serving.