PREHEAT oven to 400 degrees. Oil an 8 x 8-inch baking dish.
Sauce: PLACE a saucepan over medium heat and add the butter. When it’s melted and no longer foaming, stir in the garlic and flour. Cook for 30 seconds, then gradually whisk the milk into the pan. Bring to a simmer and cook until the sauce is thickened. Remove from heat and add the Parmesan, cream cheese and spinach. Stir until the spinach is wilted.
Lasagna: WHISK the egg and ricotta in a small bowl until blended.
SPOON about 1/4 cup sauce on the baking dish and top with 3 lasagna noodles, followed by ¼ cup of the ricotta, 2/3 cup chicken, 2/3 cup mozzarella, 1 tablespoon Parmesan and ½ cup of the sauce. Repeat the layers twice more and pour the remaining sauce and Parmesan over the top layer of noodles.
BAKE your lasagna uncovered for 20-25 minutes until the sauce is bubbling.
COOL the lasagna about 15-20 minutes before serving.