1. In a food processor or blender, combine the avocado, sour cream or Greek yogurt, lime juice, garlic, cilantro (if using), and a pinch of salt. Blend until smooth. Chill until ready to use.

2. In a mixing bowl, combine ground beef, chopped chipotle peppers, adobo sauce, garlic powder, smoked paprika, cumin, salt, and pepper. Mix gently.

3. Divide mixture into 4 equal portions and shape into patties.

4. Preheat grill or grill pan over medium-high heat. Lightly oil the surface.

5. Grill burgers for 4–5 minutes per side or until desired doneness. Add cheese slices during the final minute to melt.

6. Toast the brioche buns until golden.

7. Spread avocado sauce on the bottom bun, place the patty on top, add sliced avocado, tomato, lettuce, and more sauce. Top with the other bun.

8. Serve immediately with extra avocado sauce on the side.