The Key To Bobby Flay's Flavorful Jus For French Dip Sandwiches

A French dip sandwich dunked in a savory jus is the pinnacle of the hot sammie. And while the bread and wafer-thin slices of meat are essential ingredients, it's the beefy broth served alongside it that gives this comforting sandwhich a deep umami quality and a moreish texture. That's why chef Bobby Flay's recipe for this dunkable gravy doubles up on those meaty notes with the addition of a key ingredient full of natural umami character: dried porcini mushrooms.

Showcased in a YouTube clip from an episode of "Beat Bobby Flay," the restaurateur combines beef stock with dried porcini mushrooms, onion, rosemary, salt, and garlic to create a jus to serve with steak sandwiches. "Porchini mushrooms are very earthy and will elevate the flavor of the beef," he explained. 

Once the stock has cooked down and the mushrooms have rehydrated and released their intense flavor into the broth, Flay puts the whole lot in a blender and processes it lightly before straining the liquid to separate any chunkier bits of porcini. "I think it adds enough porchini flavor. I don't want to punch more flavor into it," he shares of why he strains the broth.

Porcini mushrooms are perfect for elevating a meaty gravy because they contain an amino acid called glutamate, which is responsible for lending foods a savory taste. Also found in Parmesan, seaweed, and tomatoes, this umami quality suffuses dishes with a satisfying roundness and complex quality. This is why leftover dried porcini are also perfect for turning into a powder and using as a seasoning in stews and casseroles. If you can't get hold of porcini mushrooms, consider using dried shitake mushrooms. Again boasting an intense savoriness, these fungi make an awesome substitute and are available at a cheaper price point. 

If you want to make French dip sandwiches at home, be sure to select a bread that has a dense texture, such as a deli roll or crusty baguette. That way your sandwich will retain its structure when you dip it into your meaty porcini jus. Softer breads, like a brioche bun, run the risk of absorbing too much of the gravy, becoming sodden, and falling into your bowl of broth like a cookie dipped in a hot cup of tea. Alternatively, toast up a bread roll that has a particularly tender texture so it holds up when one end is submerged in your aromatic gravy. Just be sure to serve your jus in a dip bowl with a wide mouth so you can dunk the entire end of your sandwich in without making a mess.