Make the Guinness Sauce: Mix mayonnaise, Guinness beer, Dijon mustard, honey, and paprika in a small bowl. Set aside.
Prepare the patties: In a mixing bowl, combine ground beef, salt, pepper, Worcestershire sauce, garlic powder, and onion powder. Form into 4 equal patties.
Cook the burgers: Heat a grill or skillet over medium-high heat. Cook patties for 3-4 minutes per side or until desired doneness.
Melt the cheese: Place a slice of Irish cheddar on each patty and let it melt.
Toast the buns: Spread butter on the buns and toast them in a skillet until golden.
Assemble the burgers: Spread Guinness sauce on the bottom bun, add lettuce, tomato, the cheesy burger patty, crispy bacon, and sliced red onions. Top with the bun.
Serve hot with fries, coleslaw, or a cold pint of beer!