- canola oil, for the grill
- 1 avocado, mashed
- 2 tablespoons chopped fresh basil leaves
- kosher salt and black pepper
- 1 1/4 pounds ground beef chuck
- 4 slices fresh mozzarella
- sliced tomato, for serving
- 4 potato buns
- Heat grill to medium-high. Once it is hot, clean the grill grate with a wire brush. Just before grilling, oil the grill grate.
- Combine the avocado, basil, and ¼ teaspoon each salt and pepper in a small bowl.
- Gently mix together the beef and ½ teaspoon each salt and pepper with your hands in a separate bowl until just combined. Form the beef mixture into four ¾-inch-thick patties. Use your fingers to make a shallow well in the top of each patty. (This will prevent overplumping during cooking.)
- Grill, covered, until an instant-read thermometer inserted in the center of a patty registers 140° F, 3 to 4 minutes per side for medium-rare.
- Top with the cheese and grill, covered, until the cheese melts, 30 seconds to 1 minute more.
- Stack the burgers, tomato slices, and avocado mixture on the buns.