Preheat oven to 450 degrees. Wash and dry produce. Cut 12 oz of potatoes into 1/2-inch-thick wedges. Toss potatoes on a baking sheet with a large drizzle of oil, salt, and pepper. Roast until golden and crispy, 20-25 minutes.

Arrange 4 oz of bacon in a single layer on a separate baking sheet. Roast on the bottom rack of the oven until bacon is crispy, 12-17 minutes. Transfer bacon to a paper-towel-lined plate.

Meanwhile, heat a drizzle of oil in a large pan over medium-high heat. Add 1 thinly sliced onion and season with salt and pepper. Cook, stirring, until softened and lightly browned, 8-10 minutes (add a splash of water if onions brown too quickly). Add 1/4 cup water and 1 tsp sugar. Cook, stirring, until onion is caramelized and jammy, 2-3 minutes more. Turn off heat; transfer onion to a small bowl. Wash out pan.

While onion cooks, in a small bowl, combine 1 clove finely chopped garlic, 2 TBSP mayonnaise, and a pinch of chipotle powder (add more if you like). Season with salt and pepper. Form 10 oz of ground beef into two equal-size balls; season all over with salt and pepper.

Heat a drizzle of oil in the pan used for onion over medium-high heat. When pan is very hot, add beef balls. Firmly flatten each with a spatula to create very thin patties. Cook to desired doneness, 3-4 minutes per side. Transfer patties to a plate; carefully pour out grease from pan.

Halve 2 potato buns. Melt 1 TBSP butter in the pan used for patties over medium-high heat. Add buns, cut sides down; cook until cut sides are golden brown and toasted, 1-2 minutes.

Divide toasted buns between plates; fill with patties, caramelized onion, and chipotle aioli. Top burgers with bacon. Serve burgers with potato wedges and, if desired, ketchup on the side for dipping.