To make the pastrami rub, mix together the coriander seeds and pepper. Remove the duck from the fridge, take out of the bowl, wash off and pat dry with kitchen towels. Brush the meat side of the duck with a little vegetable oil and generously apply half of the pastrami rub. Heat a dry frying pan over a medium–hot heat, cook the duck skin-side down for 3 minutes and then sear the other side for 2 minutes, or until cooked to your liking. Leave to rest.