In a large bowl, combine the cubed beef with 1/2 cup flour, salt, pepper, garlic powder, and onion powder. Toss until the beef is evenly coated.

Heat the olive oil in a large skillet or Dutch oven over medium-high heat. Add the coated beef and sear until browned on all sides. Remove the beef from the skillet and set it aside.

In the same skillet, add the diced onion, carrots, and celery. Cook until the vegetables are softened, about 5 minutes. Add the minced garlic and cook for an additional 1 minute.

Stir in the beef broth, grape juice, tomato paste, thyme, rosemary, and bay leaf. Bring the mixture to a simmer and return the seared beef to the skillet. Reduce the heat to low, cover, and let it simmer for 1 hour, or until the beef is tender.

In a small bowl, mix 2 tbsp butter and 2 tbsp flour to form a paste. Stir this paste into the beef mixture and cook for an additional 5 minutes, or until the gravy has thickened. Add the frozen peas and corn, and stir to combine.

Preheat your oven to 375°F (190°C). Roll out one pie crust and place it in the bottom of a 9-inch pie dish. Pour the beef filling into the crust. Roll out the second pie crust and place it over the filling. Crimp the edges to seal, and cut a few slits in the top crust to allow steam to escape. Brush the top crust with the beaten egg for a golden finish.

Bake the pot pie in the preheated oven for 30-35 minutes, or until the crust is golden brown and the filling is bubbly. Let it cool for 10 minutes before serving.