- 2 pounds russet potatoes (about 4), cut into 1/2-inch-thick sticks
- 1 tablespoon barbecue spice rub or chili powder
- 2 tablespoons plus 1 teaspoon olive oil
- 1/3 cup mayonnaise
- 2 tablespoons pickle relish
- 1 tablespoon ketchup
- 1 pound ground beef chuck
- kosher salt and black pepper
- 4 whole-wheat hamburger buns, split
- lettuce, sliced tomato, and sliced red onion, for serving
- Heat oven to 425° F. Dividing evenly, on 2 rimmed baking sheets, toss the potatoes with the barbecue spice rub and 2 tablespoons of the oil. Roast, tossing once, until browned and crisp, 25 to 30 minutes.
- Meanwhile, in a small bowl, mix together the mayonnaise, relish, and ketchup.
- Form the beef into 4 patties and place each between 2 sheets of wax paper; press to a ½-inch thickness. Heat the remaining teaspoon of oil in a large skillet over high heat. Season the burgers with ½ teaspoon salt and ¼ teaspoon pepper and cook to the desired doneness, 2 to 3 minutes per side for medium-rare.
- Form sandwiches with the buns, burgers, mayonnaise sauce, lettuce, tomato, and onion. Serve with the fries.