Crushed whole spices create a beautiful crust on a seared and roasted pork tenderloin. You don't need a spice grinder or mortar and pestle; place the peppercorns and coriander seeds in a ziplock bag and crush gently with a small, heavy skillet until very coarsely ground. Refrigerated potatoes are parcooked, saving you oven time. Coat and sear the pork while the oven preheats. Make the yogurt sauce while the pork and potatoes bake.