Step 1: Prepare the Filling

1. Sauté the Aromatics: In a large skillet or pot, melt the butter over medium heat. Add the onion, carrots, and celery. Sauté for 5–7 minutes until the vegetables soften and the onion becomes translucent.
2. Make the Roux: Sprinkle the flour over the vegetables and stir to coat evenly. Cook the flour for 2–3 minutes, stirring constantly, until it turns light golden.
3. Create the Creamy Sauce: Gradually whisk in the chicken broth, ensuring no lumps form. Follow with the milk, stirring continuously until the mixture thickens, about 4–5 minutes.
4. Season the Sauce: Add garlic powder, onion powder, thyme, salt, and black pepper. Stir well to combine.
5. Combine the Filling Ingredients: Add the shredded chicken, peas, and any additional vegetables you’re using. Mix until everything is evenly coated in the creamy sauce. Remove from heat.

Step 2: Make the Cheddar Biscuit Topping

1. Prepare the Dry Ingredients: In a large mixing bowl, combine flour, baking powder, baking soda, salt, garlic powder, and dried parsley.
2. Cut in the Butter: Add the cold, cubed butter to the flour mixture. Use a pastry cutter or your fingertips to incorporate the butter until the mixture resembles coarse crumbs.
3. Add the Cheese: Stir in the shredded cheddar cheese, ensuring it’s evenly distributed.
4. Bring the Dough Together: Gradually pour in the buttermilk, mixing until just combined. Be careful not to overmix, as this can make the biscuits dense.

Step 3: Assemble the Pot Pie

1. Preheat the Oven: Preheat your oven to 400°F (200°C).
2. Fill the Baking Dish: Transfer the creamy chicken and vegetable mixture into a 9×13-inch baking dish or an oven-safe skillet. Spread it out evenly.
3. Top with Biscuits: Drop spoonfuls of the biscuit dough on top of the filling, leaving some gaps for steam to escape.

Step 4: Bake the Pot Pie

1. Bake Until Golden: Place the baking dish in the oven and bake for 20–25 minutes, or until the biscuit topping is golden brown and cooked through.
2. Optional Garnish: Brush the biscuits with melted butter and sprinkle with fresh parsley or chives for extra flavor.

Step 5: Serve and Enjoy

Let the pot pie cool for a few minutes before serving. Use a large spoon to scoop portions, ensuring you get a balance of filling and biscuit in every serving.