Sriracha Mayonnaise: In a small bowl, stir together the mayonnaise and Sriracha; set aside.
In a large skillet, fry bacon over medium-high heat until crisp, about 8 minutes. Transfer to a paper-towel-lined plate.
Form beef into three equal-sized patties. Using a small glass, cut out the center of each patty to create a donut-shaped burger, combine excess meat to form the fourth patty. Season generously with salt and pepper.
Heat a cast-iron skillet to medium-high heat and melt butter. Add burgers and cook 2 minutes, then flip. Crack an egg into the center of each burger and cook, covered, until whites are set.
Meanwhile, toast the buns and spread Sriracha mayo on bottom buns. Build burgers by topping with lettuce, burger, cheddar cheese and bacon.