Add the butter to the skillet (leave all juices from cooking the chicken). Continue to heat over medium heat letting the butter melt. 4 tablespoons butter
Stir diced onion, celery, carrots and small potatoes. Cook until the onions are softened and translucent. Other veggies will be softened. Add the garlic and cook an additional 30 seconds. 1 small yellow onion
Stir in 1/4 cup flour and stir to coat all the veggies. Cook for 1-2 minutes. Then pour in the broth. Add seasonings: chicken bouillon, salt, pepper, thyme, and sage. Stir in the frozen peas. Bring this mixture to a simmer, cover and cook allowing the sauce to thicken and veggies to soften. (this takes about 15-20 minutes)
Preheat the oven to 425 degrees F.
Shred or dice up the chicken. Add the chicken to the sauce, and pour in the heavy cream. Stir to combine.
Prepare the biscuit mixture by mixing together the flour, salt, sugar, and baking powder in a food processor or bowl. Cut in the cold butter or pulse in the processor until texture is coarse and butter is distributed. Pour in the buttermilk and stir or pulse until dough forms. 2¼ cups all purpose flour
Remove the dough to a clean work surface and press together into a rectangular shape about 1/2 inch thick. Fold over one side to the center, then the other side. Press out the dough again and repeat this process for 4-5 times. Finally, press out the dough into a square approximately 8 inches by 8 inches. Cut the dough into 9 squares.
Place the biscuits on top of the pot pie, brush the tops with buttermilk, and bake for 15-20 minutes until the tops of the biscuits are golden.
Prepare the garlic herb butter by combining the melted butter, minced garlic, fresh parsley, and salt in a small bowl. Brush this over the tops of the biscuits. 2 tablespoons melted butter