In a saucepan, melt butter. Add the garlic, heavy cream, and pepper. Stirring constantly, bring to a boil and reduce heat to a simmer.
Add Parmesan cheese and keep stirring until sauce has thickened.
Spread a generous spoonful of sauce on the bottom of a 9x13 inch pan and cover with 3 cooked lasagna noodles. Follow with a layer shredded chicken, broccoli, and mozzarella. Add more sauce, and repeat to make another layer. On top of the last noodle layer, cover with the remainder of the sauce, and mozzarella.
Cover with foil and bake for 30 minutes. Remove the foil, and bake for 15 more minutes, until the cheese has browned.