Cooking with garlic is like cooking with gas. But for leftovers, smooth and mellow flavors are sometimes the best. I love "ghost garlic"—skin-on, whole cloves of garlic (about three) that have simmered over medium heat in a few tablespoons of olive oil and then been removed. The wonderful, almost silky garlic flavor lingers while there are no bothersome, burned bits to contend with. Toss the garlic with cooked penne, grated parmesan, and chunks of chicken.