Vegetable Shepherds Pie

Name: Vegetable Shepherd's Pie
Ingredients: 1 1/2 tablespoons Worcestershire sauce; 1 bunch baby turnips, halved or quartered if large; 1 large onion, diced; 1/2 bunch fresh parsley, leaves chopped (stems reserved); 2 stalks celery, cut into 1/2 inch chunks; 2 tablespoons extra virgin olive oil; 2/3 cup milk or half and half; 3 large carrots, cut into 1/2 inch chunks; 5 tablespoons unsalted butter; 6 cloves garlic, minced; 6 medium Yukon gold potatoes, peeled and diced; Freshly ground pepper; Grated parmesan cheese, for sprinkling (optional); Kosher salt