Leftover Turkey Pot Pie with Cheddar Biscuit Crust

INGREDIENTS

medium onion, cut into 1/2-inch pieces

large carrots, peeled and cut into 1/2-inch pieces

celery ribs, cut into 1/2-inch pieces

large parsnip, peeled and cut into 1/2-inch pieces

1 tsp

chopped thyme

3 tbsp

unsalted butter

1/2 lb

mushrooms, trimmed and quartered

3 1/2 cups

low sodium turkey or chicken stock

1/4 cup

all-purpose flour

4 cups

roast turkey (or chicken) meat, cut into 1/2-inch pieces

1 10 ounce package

frozen baby peas, thawed

2 cups

all-purpose flour

2 tsp

baking powder

1 tsp

baking soda

1/2 tsp

salt

1/2 tsp

black pepper

1 cup

coarsely grated cheddar cheese

1/4 cup

grated parmesan cheese

3/4 stick

cold unsalted butter, cut into 1/2-inch pieces

1 1/4 cups

well-shaken buttermilk