Combine the dry ingredients: In a big bowl, combine 1 3/4 cup all-purpose flour, 1/2 teaspoon salt, and 1 1/2 tsp baking powder.

Add fats: Add 2.3 oz unsalted butter and 4 1/2 tbsp vegetable shortening to the flour mixture. Knead quickly to form large crumbs.

Form the dough: Add 1/3 cup cold water, one tablespoon at a time. Knead the water to combine it with the crumbs and form a large dough.

Divide and let the dough rest: Turn the dough onto a clean work surface. Gather any crumbs and add them back to the dough. Divide into two. Flatten each dough ball into a round disk. Wrap in cling film and refrigerate for at least 2 hours.

Optional: this pastry can also be made in a food processor following the same order.

Sear the chicken: Heat 2 tbsp olive oil in a deep, cast-iron skillet over medium heat. Add 16 oz cubed chicken breast, 1/4 tsp salt, and 1/4 tsp black pepper. Sear for 6 minutes or until golden brown on all sides, stirring occasionally. Transfer the seared chicken to a plate and set aside.

Sauté the aromatics: Add 6 oz onions, 1 tbsp minced garlic, 3.6 oz carrots, 3.6 oz celery, and 3/4 tbsp unsalted butter to the same skillet. Stir and cook for 4 minutes or until translucent, stirring constantly. Return the chicken to the pan.

Make a roux: Add 1/3 cup all-purpose flour. Mix well so that the flour coats the chicken evenly.

Make the gravy: Add 1 1/2 cups unsalted chicken broth, 1/4 tsp salt, 1/4 tsp black pepper, 3 tbsp whole milk, 2 tbsp heavy cream, and 1/2 cup frozen peas. Stir and cook for another 5 minutes or until thickened. Turn off the heat and sprinkle with 1 1/2 tbsp chopped parsley.

Roll the bottom crust: Before you start, preheat the oven to 375°F. Then, take the first pie dough out of the fridge. Unwrap and put it on a clean, floured work surface. Apply flour onto your hands and rolling pin, and start to roll out the pastry into a flat pie crust about 1/8 inch thick.

Put the bottom crust into the baking dish: Lay the bottom crust into a 9-inch pie dish. Scoop your chicken filling into the dish and set aside.

Roll the top crust: Take the second dough out of the fridge and roll it out in the same way to form the top crust.

Put the top crust over the pie: Cover the pie with the top crust. Trim the dough around the edges of the pan, leaving about 1 inch of dough overhanging. Fold the excess dough in and tuck it underneath. Crimp around the edges of the pie with your fingers and knuckle.

Decorate the surface of the pie: Brush the surface of the pie with a beaten egg. Make 4 indentations in the middle of the top crust with a knife for the steam to come out while baking.

Bake the chicken pot pie: Bake for 45 minutes in the preheated oven.

Serve: Once the timer rings, take the pie out of the oven. Let it cool for at least 45 minutes before you cut into it and serve.