Cut pot roast into bite-sized pieces and dust lightly with flour. Dice bacon strips. Peel onions, garlic clove, and carrots. Finely chop garlic, onions, and carrots. Wash and cut mushrooms into small pieces. Pluck fresh thyme leaves from the stems.
On high heat, heat up vegetable oil in a pot and fry pot-roast cubes portion by portion for approx. 4 - 5 min. in total. Set aside. Fry the bacon over medium heat until the fat has melted. Add onions, carrots, thyme, and garlic to the pot, and lightly sauté for approx. 10 min., or until the onions become translucent. Sprinkle with cane sugar, and let it caramelize for approx. 2 min. Now add tomato paste and mushrooms and mix well. Add seared beef back to the pot. Sauté for approx. 3 more min. Deglaze with beer and let it reduce.
Pour in meat stock and add bay leaf and Worcestershire sauce. Season with salt and pepper. Reduce to low heat and with the lid on, cook for approx. 2.5 hr until the meat is tender. Stir from time to time.
Allow the finished beef mixture to cool down. Pre-heat oven to 220°C/425°F. Fit a layer of puff pastry into a parchment paper-lined baking dish. Allow the puff pastry to drape around the rim of the dish. Add the meat filling and top with cheddar. Cut second layer of puff pastry to the right lid size and lay over onto the cheese. Fold the overlapping part of the dough around the rim and pinch between your thumb and forefinger. Using a knife, cut a diamond pattern into the top layer of the puff pastry. Beat an egg and brush all the exposed puff pastry with the egg wash. Bake in the oven for approx. 30 min., or until the pie becomes golden brown. Enjoy!