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

Heat the olive oil in a large skillet 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, sliced carrots, sliced celery, and minced garlic. Cook until the vegetables are softened, about 5 minutes.

Pour in the beef broth, grape juice, and Worcestershire sauce. Stir in the dried thyme and rosemary. Bring the mixture to a simmer and let it cook for 5 minutes.

Return the seared beef to the skillet and add the frozen peas and corn. Stir well to combine. Reduce the heat to low, cover, and let it simmer for 20-25 minutes, or until the beef is tender.

Preheat your oven to 375°F (190°C). Roll out the puff pastry sheet on a lightly floured surface to fit the size of your pie dish.

Transfer the beef and vegetable mixture to a pie dish. Place the puff pastry over the top, trimming any excess. Crimp the edges to seal and cut a few small slits in the top to allow steam to escape. Brush the pastry with the beaten egg for a golden finish.

Bake in the preheated oven for 25-30 minutes, or until the pastry is golden brown and flaky. Let it cool for a few minutes before serving.