Using a mortar and pestle, mince together garlic cloves with salt. Stir in olive oil, peppercorns, and chopped rosemary. If you cannot find mixed peppercorns use black peppercorns instead.
For lamb leg, rack of lamb, or fattier cuts, score the fat with a sharp knife 1/8" deep. Apply rub to meat, cover with plastic wrap and place into the refrigerator between 1-4 hours before cooking.Chops for 1 hour, medium sized roasts and ribs for 2-4, and lamb leg for 4 hours.
If roasting or grilling a lamb leg, then double or triple this recipe, and apply as all over.
Do not save any rub that has come into contact with raw meat.