These are Spanish-inspired burgers. Romesco, a roasted red pepper pesto, goes perfectly with the beef, and sharp Manchego cheese may just usurp Cheddar as the ultimate cheeseburger topping. You can prepare the Romesco up to two weeks ahead. Add sliced tomatoes and lettuce if you wish, but frankly, less is more here to better appreciate the flavors. I saw this recipe being prepared on a local news station. It was prepared by Rick Rodgers, an author of more than 25 cookbooks.