Heat 2 tablespoon oil in a Dutch oven over medium-high heat. Sear beef chunks for 3-4 minutes per side until browned, working in batches to avoid crowding. Transfer to a plate and set aside.
2 lbs beef chuck
In the same pan, sauté onions, carrots, and celery for 5 minutes until softened. Add butter and flour, stirring constantly for 2-3 minutes until the roux turns golden and smells nutty.
1 large onion, 3 medium carrots, 2 stalks celery, 4 tbsp butter, 0.25 cup all-purpose flour
Pour in beef broth while whisking to prevent lumps. Return beef to the pan, add potatoes, and simmer partially covered for 25-30 minutes until beef is fork-tender and gravy coats the back of a spoon. Season with salt and pepper.
2 cups beef broth, 2 lbs beef chuck, 3 medium potatoes
Transfer filling to an oven-safe pie dish and let cool 10 minutes. Drape pie crust over the top, trim excess, crimp edges, cut 3-4 vent slits, brush with beaten egg, and chill for 20 minutes.
1 package pie crust or puff pastry, 1 egg egg
Bake at 375°F for 35-40 minutes until crust is golden brown and filling bubbles through vents. Let rest 10 minutes before serving to set the gravy.
1 package pie crust or puff pastry
