Let's say you owned a restaurant, which means you're in the business of making customers happy. Would you insist that the customers have to eat the food while it's hot, with exactly three shakes of hot sauce, and always with an iced tea? Probably not. However, some places do put strict rules on how their food should be enjoyed. For example, Louis' Lunch, the legendary burger joint in New Haven, Connecticut. This story, from America’s Test Kitchen reporter Alex DiPalma and their podcast Proof, is about why you shouldn't even think about adding ketchup to your burger at Louis'.

America's Test Kitchen
The Splendid Table frequently visits with the test cooks at America’s Test Kitchen to discuss a wide range of topics including recipes, ingredients, techniques and kitchen equipment.