Pre-heat the oven to 400 and line a sheet tray with aluminum foil. Fit a cooling rack on top of the sheet tray and lay the bacon out in a single layer on the rack. This will allow heat to go all around the bacon and the grease to pool on the aluminum foil. Cook the bacon in the oven for around 20-22 minutes, until it is completely crisp. Take it out and let it cool enough to handle. Meanwhile, toast the two buns. Butter them generously, then pile 4 pieces of bacon onto each of the bottom buns. Squirt a generous amount of HP sauce on top of the bacon, then close up the sandwiches and enjoy the simple yumminess!