Preheat the Oven: Preheat oven to 425°F. Line a rimmed baking sheet with parchment paper for easy cleanup.
Cook the Beef: In a large skillet over medium heat, heat 1 tablespoon extra virgin olive oil. Add 1 pound lean ground beef and cook, breaking it apart with a spatula, until browned and cooked through, about 5–6 minutes. Drain excess grease if needed.
Make the Sauce: In a medium bowl, whisk together 1 8 ounce can tomato sauce, 1 –2 chipotle peppers in adobo,1 tablespoon adobo sauce, 2 tablespoons packed light brown sugar, 2 tablespoons Worcestershire sauce, 1 teaspoon onion powder, 1/2 teaspoon garlic powder, 1 teaspoon ground cumin, 1 teaspoon New Mexico chili powder, 1 teaspoon kosher salt, and 1/2 teaspoon fresh ground black pepper until smooth.
Toast the Buns: Place 4 hamburger buns cut side up on the prepared baking sheet. Spread lightly with 1 tablespoon unsalted butter. Bake for 5–7 minutes, or until golden brown and lightly crisp.
Simmer the Filling: Pour the chipotle sauce into the skillet with the cooked beef. Stir to combine and let simmer for 4–5 minutes, until the sauce thickens and clings to the meat. Remove from heat.
Assemble and Serve: Spoon the smoky beef mixture onto toasted buns and top each with 2 of the 8 pickle slices. Serve hot and messy!