The fine dark seeds of the common field poppy have historically been used in baking, added to batter or dough, or as a topping for biscuits and bread. In Eastern Europe the seeds are boiled in milk or water, ground and sweetened to produce a paste filling for pastries. The seeds are also pressed to produce culinary oil, much valued in France.
Try them toasted and stirred into mash or sprinkled on salads, veg or pasta.