Chipotle Cheeseburgers

Name: Chipotle Cheeseburgers
Cook time: 30 min
Total time: 30 min
Cuisine: American, Mexican, Latin American
Ingredients: 1 1/2 pounds ground beef, 80/20; 1/4 teaspoon dried oregano, preferably Mexican; 1/4 teaspoon kosher salt; 1/8 teaspoon garlic powder; Freshly ground black pepper; 1/2 cup sour cream; 3 chipotle chiles in adobo sauce, finely chopped, plus 3 tablespoons adobo sauce; 1/3 cup finely chopped white onion; 1 cup loosely packed fresh cilantro leaves, finely chopped; 4 whole-wheat buns, split; 2 tablespoons unsalted butter, softened; 4 slices Cheddar; 1 avocado, thinly sliced; Tomato slices, for topping; Green-leaf lettuce leaves, for topping; Red onion slices, for topping