Preheat your smoker to 225°F.

Use a sharp knife to lightly score the skin side of the duck breast in a criss cross pattern, being careful not to cut too deep (you should not cut through to the meat).

Season the duck breasts with the dry rub and let sit until the smoker is ready.

Place duck breasts skin side up directly on the smoker grill grates. Insert a digital meat thermometer. Smoke for approximately 60 minutes, until the internal temperature reads 115°F. Remove the duck from the grill.

Turn up the grill temperature to 450°F with a cast iron pan inside, or heat the cast iron pan on the stovetop over high heat until very hot.

Place the duck, skin side down, on the cast iron pan and sear until crispy and the internal temperature reaches 130°F. Cover loosely with foil and allow smoked duck breast to rest for 5 - 10 minutes before slicing.