Heat a heavy skillet over medium heat. Add the peppercorns, mustard seeds, coriander seeds, and dill seeds and toast until very fragrant and the mustard seeds begin to pop. Be careful not to scorch or spices will become bitter. Remove from heat and let cool completely. Transfer the cooled spices to a ziplock bag and use a rolling pin or bottom of the skillet to coarsely crush the spices. Add the remaining ingredients and coarsely crush again. Transfer the blend to a jar with a lid and store in a cool, dark place. For best flavor use within a month. Makes about 1/4 cup.