Brown the sausage in a skillet. Wash the apples and cut off the tops. Remove the cores and hollow out the apples, leaving just a ½-inch thickness. Chop the removed apple flesh and mix with the browned sausage, brown sugar, cinnamon, and lemon rind. Fill the apples with the mixture, place into a baking dish, cover, and bake at 375 degrees F until tender, about 40 minutes.