PREHEAT GRILL: Preheat a grill to high heat, about 450°F.
FORM PATTIES: Divide 2 pounds ground beef into 4 equal portions and shape into patties about ½ inch thick. Form each patty slightly larger than the hamburger buns and press a shallow indentation in the center so the burgers cook evenly.
SEASON BURGERS: Sprinkle 2 teaspoons Tex-Mex seasoning, 1 teaspoon kosher salt, and ½ teaspoon fresh ground black pepper evenly over both sides of the patties. Gently press the seasoning into the meat.
GRILL BURGERS: Place the patties on the grill and cook for about 4 to 5 minutes until a browned crust forms. Flip the burgers and cook another 4 minutes for medium doneness, until the internal temperature reaches about 160°F.
ADD CHEESE: During the last minute of cooking, sprinkle about ¼ cup shredded cheddar cheese over each burger and close the grill lid until the cheese melts.
TOAST BUNS: Spread the cut sides of the 4 hamburger buns with the softened butter. Place the buns butter-side down on the grill and toast for about 1 minute until golden brown.
ASSEMBLE BURGERS: Spread about ¼ cup guacamole on the bottom half of each bun. Place the cheeseburger on top, then spoon about ¼ cup pico de gallo over the burger.
SERVE: Place the top buns on the burgers and serve immediately while warm.
Notes
Make-Ahead: The burger patties can be formed up to 1 day ahead and stored covered in the refrigerator until ready to grill.Storage: Store leftover cooked burgers in an airtight container in the refrigerator for up to 3 days.Reheating: Reheat burgers in a skillet over medium-low heat or in a 325°F oven for about 10 minutes until warmed through.Freezing: Raw burger patties can be frozen for up to 3 months. Place parchment paper between patties and store in a freezer-safe bag.Stovetop Method: If you don’t have a grill, cook the burgers in a large skillet or cast iron pan. Heat the skillet over medium-high heat and add the patties. Cook for about 4 to 5 minutes until a browned crust forms. Flip and cook another 4 minutes until the internal temperature reaches about 160°F. Sprinkle the cheddar cheese on top during the last minute of cooking and cover the pan briefly to melt the cheese. Toast the buttered buns in the same skillet for about 30 to 60 seconds until golden.