Preheat oven to 375 . Separate the bacon slices and cut into thirds. Place the brown sugar in a shallow bowl. Spread one side of each bacon slice with a thin layer of honey mustard. Dip both sides of each slice of bacon in the brown sugar to coat thoroughly. Place the bacon on a rack over a pan to catch the drippings.
Bake in the upper third of the oven for 20 minutes. Finish browning the bacon under the broiler, watching closely. Let cool slightly but not too long or the bacon will stick to the rack. Transfer to paper towels to drain. Serve at room temperature.