Prep and preheat: Set your oven to 400°F (200°C). Pat the chicken dry and season with salt and pepper.

Brown the chicken: Heat a large oven-safe skillet (12-inch cast iron works great) over medium-high heat. Add 1 tablespoon olive oil and 1 tablespoon butter. Sear the chicken until lightly browned and just cooked through, about 4–6 minutes per side. Remove to a plate and let rest.

Sauté the aromatics: Reduce heat to medium. Add 2 tablespoons butter, then the onion, carrots, and celery. Cook until softened, 6–8 minutes. Stir in garlic and thyme; cook 30 seconds until fragrant.

Make the roux: Sprinkle the flour over the vegetables and stir to coat. Cook 1–2 minutes, stirring, until the flour smells toasty and no dry spots remain.

Add liquids: Slowly whisk in the chicken broth, scraping up any browned bits. Stir in the milk or half-and-half and the bay leaf. Simmer 4–6 minutes until the sauce is thick and creamy.

Chop the chicken: While the sauce simmers, chop or shred the chicken into bite-size pieces.

Combine and season: Stir the chicken, peas, and parsley into the sauce. Taste and season with salt, pepper, and a splash of lemon juice if you like a brighter finish. The filling should be thick but spoonable. If too thick, add a splash of broth; if too thin, simmer 2–3 more minutes.

Add the topping: Puff pastry: Lay the sheet over the skillet, tuck in edges, and cut a few slits for steam. Brush with egg wash if using.

Biscuit dough: Arrange biscuits on top of the filling, leaving small gaps so steam can escape.

Drop biscuits: Spoon mounds evenly over the surface.

Bake: Transfer the skillet to the oven. Bake 18–25 minutes, until the topping is golden and cooked through and the filling is bubbly around the edges.

Rest and serve: Let the pot pie rest 10 minutes so the filling sets slightly. Sprinkle with extra parsley and serve warm.