Let the frozen dough thaw 4-6 hours ahead of baking
Heat 1 tbsp vegetable oil in a large skillet over medium-high heat. Add the beef cubes, season with salt and pepper, and brown on all sides for about 6-8 minutes. Brown in batches if needed.
Transfer browned beef to a plate. In the same skillet, add onions and garlic, cooking until softened and fragrant, about 4-5 minutes.
Stir in the tomato paste and thyme, cooking for another minute. Sprinkle the flour over the mixture and stir well to coat.
Slowly pour in the Guinness, scraping the pan to lift any browned bits. Return the beef to the skillet, reduce heat to low, cover, and simmer gently for 45 minutes to 1 hour until the meat is tender and the sauce thickens. Stir occasionally.
Preheat oven to 400°F (200°C). Roll out the dough to about 1/8 inch thickness. Use a round cutter or knife to cut circles about 4-5 inches wide.
Spoon about 2 tablespoons of cooled beef filling onto one half of each dough circle. Moisten edges with water, fold over to form a half-moon, and press edges firmly with a fork to seal.
Place pies on a parchment-lined baking sheet. Brush tops with beaten egg. Cut a small slit in each for steam to escape.
Bake for 20-25 minutes or until golden and crispy, rotating the baking sheet halfway through.
