Step 1

Preheat oven to 350°F. Spray an 8x8-inch baking dish with nonstick cooking spray.

Step 2

In a large saucepan over medium heat, melt the butter. Add the onion and cook 4 minutes, or until translucent. Stir in the garlic and flour and cook 30 seconds. Gradually whisk the milk into the pan. Bring to a simmer and cook until thickened. Remove from the heat and stir in the parmesan, cream cheese, chicken, spinach, salt, and pepper. Continue stirring until the spinach is wilted.

Step 3

In a small bowl, whisk the egg and ricotta until smooth.

Step 4

In the bottom of the baking dish, spread about 1/4 cup sauce. Add 3 noodles over the top, followed by even layers of 1/4 cup ricotta mixture, 1/2 cup sauce, and 2/3 cup mozzarella. Repeat the layers 2 more times and pour any remaining sauce over the top. Sprinkle with additional mozzarella cheese. Cover with foil.

Step 5

Bake 35 to 45 minutes, or until the sauce is bubbling. Remove the foil and broil 2 to 3 minutes, or until the cheese is melted.

Step 6

Let cool for 15 to 20 minutes before slicing.