Easy Sweet Potato Shepherds Pie

Name: Easy Sweet Potato Shepherds Pie
Ingredients: * 1 teaspoon oil (i used grape seed oil); * 1 pound lean (97% or better) ground turkey; * 1 medium white onion, diced; * 2 rib celery, diced; * 2 medium carrot or parsnip, diced; * 4 ounce fresh mushroom, sliced; * 1/2 cup frozen pea; * 2 tablespoon all purpose flour; * 8 ounce (1 liquid cup) chicken stock; * 1/2 teaspoon poultry seasoning; * 1/4 teaspoon ground thyme leaf; * 1 teaspoon worcestershire sauce; * 1/4 teaspoon salt (more, if desired); * 1/4 teaspoon ground black pepper (more, if desired); * 2 cup prepared mashed sweet potato (1 pound package simply; potato mashed sweet potato); * finely chopped flat leaf parsley, for garnish