Nothing beats a sizzling hot platter of fajitas--well, except maybe this burger! We took the fun of a fajita platter and turned it into a decadent burger that is loaded with peppers, onions and plenty of pepper jack cheese for some kick. Worcestershire sauce brings salty umami to both the guacamole and the burger patties.
Prepare a grill for medium indirect heat (for a gas grill, leave one or two burners on low or off; for a charcoal grill, bank the coals on one side of grill).
Combine the avocado, sour cream, hot sauce, lime juice, 1 tablespoon of the Worcestershire sauce and 1/2 teaspoon salt in a medium bowl and mash together with a potato masher or the back of a fork. Stir in the cilantro, cover and set aside.
Combine the oil, bell peppers, onion, jalapeno, 1 tablespoon of the chile powder, 1 teaspoon salt and several grinds of black pepper in a large bowl and toss to combine; set aside.
Combine the beef, remaining 1 tablespoon Worcestershire sauce, remaining 1 teaspoon chile powder, 1 teaspoon salt and several grinds of black pepper in a large bowl and mix well. Divide the mixture into fourths and shape into patties.
Lightly brush the grill grates with oil. Put the bell pepper mixture in an open grill basket and cook over direct heat, tossing frequently, until the peppers and onions are golden and tender, 12 to 15 minutes. Move the basket over indirect heat. Put the patties over direct heat. Grill the patties until marked on the bottom, about 3 minutes. Flip and cook about 2 minutes, then top each patty with 1 slice of pepper jack cheese. Cover the grill and cook until the cheese is melted and the patties are marked on the other side and slightly firm, about 1 minute more for medium rare. Remove the patties and pepper mixture to a serving platter.
Spread the guacamole on both sides of the buns and top with the patties and pepper mixture.