Begin frying potatoes: Melt 1 tablespoon butter in a skillet over medium heat. Add potatoes and fry for 10 minutes, stirring often. Turn off heat and set aside.

Meanwhile, prepare duck: Pat duck dry with paper towels. Season with salt and pepper on both sides. Run a knife diagonally over the skin to score it in a crisscross pattern, being careful not to cut all the way through the skin. This will help the fat render (meaning change from solid form to liquid form) as it cooks.

Begin cooking duck: Heat a cast iron skillet over medium heat. Add duck, skin side down. Cook 8 minutes without moving. Pick up the skillet with one hand and use tongs or the back of a spoon with your other hand to hold the duck against the skillet. Carefully pour the melted duck fat out of the pan into a bowl. Put the skillet back on the stove.

Continue frying potatoes: Add 2 tablespoons of the melted duck fat to the skillet with the potatoes. Put the potatoes back on medium heat and fry, stirring occasionally, until fully cooked and crispy, 15 to 20 more minutes. Add salt and pepper to taste.

While potatoes fry, continue cooking duck: Turn heat down to medium-low. Continue cooking duck until the skin has rendered most of its fat and is crispy, another 5 to 10 minutes. Every few minutes, as liquid fat collects in the pan, pour it out into the bowl. When skin is crispy, flip the duck breasts over and cook for another 3 to 8 minutes, depending how you like it cooked. Remove duck to a plate and cover loosely with aluminum foil. Let rest for 10 minutes.

While duck is resting, make the sauce: Use the same skillet you cooked the duck in, but pour off excess fat. Add cherries, broth, wine, honey, and orange zest. Bring to a boil over medium high heat and cook until sauce develops a syrupy consistency, about 3 minutes. Remove from heat. Add remaining 1 tablespoon butter and stir until melted. Add salt and pepper to taste.

To serve: Slice duck breasts against the grain. Serve with sauce and potatoes.