Preheat oven to 325°.
Prepare the Meatballs: In a large bowl, combine egg, Doritos, milk, cumin, cayenne, salt and pepper. Let stand for 5 minutes. Process garlic, onion, celery and carrot in a food processor until finely chopped.
Add ground meats and finely chopped vegetables to oatmeal mixture. Add herbs to bowl. Gently toss until thoroughly combined. Be careful not to over mix. Form mixture into 1” meatballs and place on sheet pans. Chill for at least 30 minutes in refrigerator.
Preheat oven to 350 degrees. Remove meatballs from fridge. Heat a large skillet with olive or vegetable oil. Sear the meatballs until golden brown on all sides and finish in the oven until cooked through, about 4 minutes.