Combine miso, soy sauce, mirin & sugar in a small mixing bowl, be sure to fully dissolve the miso paste.
Rinse the ducks and make sure to fully pat dry, paying extra attention to the skin side.
Heat the oven to 355 degrees F.
Heat a frying pan & add a bit of neutral oil to keep the duck from sticking. Place the duck skin-side down and fry for about 5 minutes until the skin is golden and crispy. Turn the duck breasts over and cook for 2 more minutes.
Remove from the heat and carefully drain off the duck fat. (Pro tip Save the duck fat and use to stir fry leafy greens as a side dish) One the duck fat is drained carefully spoon over the miso glaze mixture. I used a silicone pastry brush to make sure that the breasts were coated evenly.
Place uncovered in your pre heated oven cook for about 8–10 minutes and let rest before carving into slices. You can serve as is or drizzle the remaining glaze in the pan over the duck slices.