optional: tomatoes, pickles, lettuce, onion, avocado, cheese, for topping
Combine all ingredients in a food processor and pulse 15-20 times to thoroughly combine and puree chipotle pepper.
Divide meat into 4 equal portions. Roll each portion into a ball with your hands, then flatten into a disc, making each patty center slightly thinner than around the edges. Mix together onion powder, salt, pepper, paprika, and celery salt. Sprinkle patties with seasonings on both sides and grill over medium heat for about 8 minutes per side, or until meat is cooked to your preferred doneness.
Allow patties to rest for 3-5 minutes when removed from grill. Place patties on buns, smother with chipotle sauce, and add additional desired toppings.