Adjust rack to top position and preheat oven to 450 degrees. Wash and dry produce.

Cut potatoes into ½-inch-thick wedges. Halve, peel, and thinly slice onion. Thinly slice tomato; season with salt and pepper. Trim and discard root end from lettuce; thinly slice leaves.

Toss potatoes on a baking sheet with a large drizzle of oil, half the garlic powder, a big pinch of salt, and pepper. Roast on top rack until golden brown, 20-25 minutes.

Turn off heat; transfer to a medium bowl. Wipe out pan.

Meanwhile, in a large bowl, combine beef*, half the blue cheese, remaining garlic powder, salt (we used ¾ tsp; 1½ tsp for 4 servings), and pepper. Form into two patties (four patties for 4), each slightly wider than a burger bun.

Once onion is done, heat a drizzle of oil in same pan over medium-high heat. Add patties and cook to desired doneness, 3-5 minutes per side.

Halve and toast buns.

Spread cut sides of bottom buns with as much mayonnaise as you like. Fill buns with patties, caramelized onion, remaining blue cheese, tomato, and lettuce.

Divide burgers and potato wedges between plates and serve. TIP: If you have ketchup on hand, serve some on the side for dipping.