Take oven rack and pre heat in the oven at 425 degrees.
Melt unsalted butter in a 12-by-2 inch cast iron skillet at medium heat. Sauté the onions for about 8 to 10 minutes till they turned golden brown.
Add and stir the floor in it to sauté the mixture for a few minutes.
Add chicken broth and heavy cream into the mixture while stirring. After this, add fresh thyme, rosemary, salt and pepper according to taste.
Cook the mixture until it starts simmering. Reduce the heat flame to make the mixture consistency slightly thick.
Add mixed vegetables and chicken into the pot and cook for only 30 seconds to defrost and warm them. Remove the stock from the heat and set aside.
Take a large mixing bowl and whisk flour, baking soda, baking powder, and salt together. Mix them thoroughly to homogenize the mixture and keep it aside.
Take a microwave-safe dish and melt two-thirds of the butter. Remove partially melted butter from the flame and try to melt it with the help of a whisker.
Add buttermilk into the melted butter and continue stirring while adding milk to avoid formation of clumps.
Combine the buttermilk and flour mixture together with the help of a rubber spatula.
Take a small measuring cup, grease it, and scoop out dough and place it on pot pie filling in skillet. Do the same process again and again to form 8 biscuits.
Bake these biscuits in the oven for about 15 to 25 minutes depending upon whether you want light golden or golden brown biscuits.
Garnish your Pioneer Woman Chicken Pot Pie with crispy biscuits and chopped parsley to enjoy a healthy meal.