Heat a large (12 inch preferred) cast iron skillet over medium-high heat and melt the butter. Once melted, add the onion, carrots, celery, potato and a good pinch of salt and pepper. Cook about 5 minutes until softened and slightly browned. Add garlic and sauté for one minute.
Sprinkle flour over cooked veggies and stir to combine. Slowly add the chicken stock while stirring. Be sure to scrape any bits off the bottom.
Stir in milk and herbs. Bring to a simmer - lower heat, if necessary. Simmer for 4-5 minutes until thickened.
Peas. Stir in turkey and peas.
Biscuits. Combine melted butter with the herbs. Top the pot pie with the biscuits and brush tops with the melted herb butter.
Bake in preheated oven for 25-30 minutes until the biscuits are golden brown (make sure to check the bottom of the biscuits, the tops will cook faster) and the pot pie filling is bubbly. After 10-15 minutes and the biscuit tops are brown, you can loosely tent with foil so they don't get too dark.
Allow to cool for 5 minutes before serving and enjoying.
