PREHEAT OVEN TO 400F. Either grease the muffin pans or line them with paper baking cups. Using the small side of the grater, grate the rind from the oranges, removing only the bright orange part, and set aside. With a small, sharp knife, remove all the remaining peel and, if necessary, trim the oranges all around so that the slices will fit into the bottom of your muffin pans. Cut the oranges into slices about 1/4-inch thick, pick out all the seeds and set the slices aside. Put about 1 teaspoon honey in the bottom of each muffin cup, and place an orange slice on top. Combine the flour, oatmeal, baking powder, salt and sugar in a large mixing bowl, and stir with a fork or wire whisk to mix. Add the reserved grated orange rind, the eggs, milk, and melted butter, and stir just until mixed. Spoon the batter over the orange slices, filling each cup about 2/3 full. Bake for 15-to-20 minutes, or until a toothpick inserted in the center of a muffin comes out clean. Remove from the oven and serve warm.