Crush the Peppercorns by covering the peppercorns in a towel and smashing with a mallet. (Do not use a grinder, unless you can do a VERY course ground.)
Mix HALF of the the crushed Peppercorns, and the Salt and Pepper with the defrosted Ground Beef. Then let sit for an hour.
In a bowl, add the remaining crushed Peppercorns, Garlic Powder, Cajun Seasonings, and mustard.
Form the ground beef into 4 patties, then coat the patties in the peppercorn mixture.
Place on the grill, or a frying pan and cook to order, until the outside is crusted with black pepper and spices, then serve.