Shake Shack has one. McDonalds has a song about theirs; Do you remember it?
Two all beef patties, special sauce, lettuce … on a sesame seed bun?
The basic secret sauce is just three ingredients. After that you can get creative with a fourth.
For the base you need ketchup, mayonnaise and a third sauce (hot sauce, soy sauce, sriracha, gochujang sauce, chutney).
Remember that you can always add, but it is difficult to take away. Start with equal parts ketchup and mayonnaise. Hellman’s is the mayo that I usually have in my fridge. Duke’s is another popular one. Duke’s seems a little more tangy to me. You can also go richer and creamier with a Japanese mayo like Kewpie. Then, add in no more than two other ingredients.
Put in one part mayonnaise. (You can always add a little more later to balance it out.) Then add in an equal part ketchup.*
Everyone has their favourite hot sauce in the fridge. Go simple and mild or wild and spicy. As a cultural melting pot that cares more and more about our food, we are becoming adventurous with flavours. The result is that there is a greater variety of options on the shelves. In the Boston area you can find hot sauces with origins from Haiti to Hawaii.**
One, two, three and done… Stop here and you’re already ahead of the game.
…unless you want to go to the next level. This is where you can really have some fun, just don’t add more than one. I love extra tang so pickle juice is a favourite addition of mine.
You can add: pickle juice, lemon zest, roasted garlic, raw grated garlic, ginger, nigella seeds, celery salt, a favourite dry or fresh herb. If you use the basic trio of ketchup, mayo and hot sauce then you can also add a dash of soy sauce, sriracha, or gochujang. Try adding in some finely chopped kimchi, chutney, or Haitian pikliz. The rule is to keep it simple to not muddle flavours so only add one extra ingredient (ok maybe two).
*Have you been to the Ketchup aisle lately? There are so many different kinds. If you feel like trying a new version go for it. I’m a fan of the jalapeño one.