Cut the chuck roast into 1 " chunks and season liberally with salt and pepper. Heat 2 tablespoons of the olive oil in a large stock pot over medium high heat. In two batches to prevent overcrowding, brown the beef all over. Remove and repeat with remaining beef. Set aside.
Into the same pot, add the remaining tablespoon of olive oil and add the diced onions. Cook for 5, or until the onion begins to soften and turn translucent. Add the mushrooms and cook until the mushroom begins to turn brown around the edges, about 5 minutes more. Next add the minced garlic and cook for 1 minute, or until the garlic becomes fragrant. Add the diced carrots and celery.
Sprinkle the flour over the vegetable mixture and mix well. Cook for 1 minute. Whisk in the beer, beef stock, garlic powder, thyme and cooked beef. Bring the mixture to a low simmer and cover. Allow to simmer on low for 1 hour and 30 minutes, stirring often, until the beef becomes fork tender.
When the mixture is getting close to being done, cook the bacon. Chop the bacon (or use scissors!) and cook over medium high heat, until cooked through and crispy golden. Set the bacon aside on a paper towel lined plate to absorb excess grease.
When the beef mixture is done cooking, add the bacon and frozen peas. Season to taste with salt and pepper. Pour the mixture into a large casserole dish and top with two sheets of the frozen puff pastry, folding and pressing the edges of the pastry dough like a pie. Make an egg wash by whisking the egg with 2 tablespoons of water, and brush the puff pastry all over. Discard leftover egg wash. Using a sharp kitchen knife, make three slits in the center of the puff pastry.
Bake the meat pie for 30-35 minutes, until the puff pastry is golden brown. Allow to cool for 10 minutes, serve and enjoy!