Preheat oven to 375 degrees (190 Celsius).
Score duck breast on fatty side in diamond pattern. Heat skillet over medium-high heat.
Cook breast, fat side down, for about 5 minutes, or until browned and duck fat is released. Remove from heat. Drain all but 2 tablespoons (30mL) duck fat.
Transfer duck to a baking tray, bake in centre of oven for 15 to 20 minutes, or until thermometer inserted to centre reaches 160 degrees (70 Celsius). Remove from oven and let rest 5 minutes.
Meanwhile, in skillet over medium heat, sauté shallots until translucent, about 2 minutes. Add garlic, and sauté until fragrant, about 1 minute. Add apples and cherries. Add port, balsamic vinegar and maple syrup and cook, scraping bottom of pan, until liquid is reduced by half, and cherries and apples are tender, about 5 minutes.
Slice duck breast thinly across the grain. Serve with apple cherry port sauce.