Yet, I never thought to add it to mac and cheese—until I came across Anthony Bourdain’s recipe. It's Worcestershire sauce.

Insider visited the Lea & Perrins factory to see how Worcestershire sauce is made ... and a British favourite, cheese on toast. More from Regional Eats ...

Worcestershire sauce contains anchovies ... Sprinkle it over sausages, steaks, chops and toasted cheese or use it in drinks such as a classic Bloody Mary.

Cook for a minute or two, then gradually add the stout and the Worcestershire sauce, stirring constantly until smooth. Bring to the boil and immediately reduce the heat. Add the cheese and stir ...