I used a my mortar & pestle to crush the spices.
Rosemary and Peppercorn Encrusted Pork Tenderloin
2 tsp peppercorns, crushed
1 tsp dried rosemary, crushed
½ tsp kosher salt
½ tsp fennel seeds, crushed
½ tsp celery seeds, crushed
½ tsp mustard seeds, crushed
1 (1 lb) pork tenderloin, trimmed
Preheat oven to 425.
Combine first 6 ingredients; rub over pork. Place pork in a shallow roasting pan coated with cooking spray. Bake at 425 for 30 minutes or until a thermometer registers 160 (slightly pink). Let stand 5 minutes; cut into thin slices.