To make the pie crust, add diced butter, shortening, flour, and salt to a food processor and pulse 8 to 12 times until butter is evenly incorporated into the flour and about the size of peas. Then with the machine running continuously, add the ice water slowly until the dough begins to form a ball. Gather the dough on a floured surface into 2 even disks, wrap in plastic wrap and refrigerate until ready to use.
Prepare the filling. Season chicken breast on both sides with salt and pepper. Heat a deep skillet to medium high and add 1 Tbsp olive oil to the pan. Sear the chicken breast on both sides for about 8-10 minutes until evenly browned. Transfer the breast to a sheet pan and place in a 350 degree oven to finish cooking (about 25 min, or until thermometer reads 165)
Add diced onion, celery, and carrot to the skillet and scrape the brown bits off the pan. Season with salt and pepper and sauté for about 5 minutes. Next add garlic and diced potatoes, followed by the wine, and let simmer for 5 minutes to allow the alcohol to burn off. Once most of the liquid has evaporated add the butter. Once melted and bubbling add the flour and stir to fully incorporate. Slowly add the chicken stock while stirring continuously. The filling will thicken once it reaches a boil. Cook for another 5 minutes or so to allow the flavors to marry. Turn off the heat and add the fresh herbs, peas, and cooked chicken breast, cut into chunks. Let cool.
Flour a countertop or cutting board and roll out one pie crust to top your pot pie. You can freeze the other dough for another recipe. Transfer cooled filling to a pie dish and top with the pie crust. Flute the edges and make slits in the top to allow steam to escape while cooking. Place pie dish on a cookie sheet lined with foil (for spills) and bake in a 400 degree oven for 40 minutes or until filling is bubbling and the crust is golden brown. Let cool for 10-15 min before serving.
