To give an authentic flavor to this savory stew, look for Hungarian sweet paprika in the spice section of well-stocked supermarkets or specialty-food stores. Unlike most mild American paprika, which adds little but color, this dark red powder has a rich, aromatic flavor that captures the essence of the dried and milled paprika peppers from which it is made. Hungarian paprika is produced in five grades based on piquancy and heat; the sweet type, called for in this recipe, is the most versatile and easiest to find.