Pat the breast completely dry with paper towels — moisture kills crispiness. Score the skin in a crosshatch pattern, cuts spaced 3/4 to 1 inch apart; cut through fat only, not the flesh. Season both sides with salt and pepper. For best results, refrigerate uncovered up to 8 hours ahead. If the breast is uneven, lightly pound between plastic wrap to roughly 1/2 to 3/4 inch thickness for even cooking.

Place the duck breast skin-side down in a cold heavy skillet (cast iron or stainless). Bring heat to medium-high and let the fat render out gradually — this cold-start method is key to crispy skin. Drain excess fat from the pan as it accumulates. Cook skin-side down 7–10 minutes until the skin is deep golden brown and visibly crisp. Don't rush it. Flip, reduce heat to medium, and cook the flesh side 4–8 minutes more. Target internal temp: 135°F for medium-rare — check with an instant-read thermometer at the thickest part. Total cook time: roughly 12–18 minutes. Optionally finish in a 250°F oven after searing the flesh side for more even interior heat.

Transfer duck breast to a cutting board or rack and tent loosely with foil. Rest at least 5–10 minutes before slicing — this keeps the juices inside. At 135°F the center will be slightly pink (medium-rare). Slice thinly on a diagonal or into 1-inch widthwise pieces and fan on the plate. Use pan drippings for a quick sauce if desired. Note: USDA recommends 165°F for poultry; 135°F is a culinary medium-rare preference — cook to your comfort level.