Elevate Your French Dip With Bobby Flay's Signature Jus

What's not to love about the French dip? Between hearty roast beef, melty cheese, and a flavor-packed au jus for dipping, it is easily one of the greatest sandwiches of all time. A crucial part of the dish is the au jus, which is typically made with drippings from the roast beef. Celebrity chef Bobby Flay uses a special ingredient in his signature jus that has our collective mouths watering: porcini mushrooms.

Flay demonstrates how to prepare his signature au jus on an episode of Food Network's "Beat Bobby Flay," and it's actually pretty simple. He combines beef broth, dried porcini mushrooms, onion, rosemary, and garlic. After simmering this gourmet concoction for a bit, Flay then purees the broth in a blender and strains the ingredients. "I think it has enough porcini flavor; I don't want to punch more flavor into it," he says on the episode titled "If I Dip, You Dip, We Dip."

Why do porcini mushrooms belong in a French dip au jus? They're earthy and full of umami. According to Flay, "They elevate the flavor of the beef."

You could definitely make a version of Bobby Flay's signature au jus with fresh porcinis, but it won't be as convenient or flavorful. Dried porcinis (and other mushrooms) are a great pantry item to keep on hand. While you may only find fresh porcinis in your local supermarket when they're in season — typically between September and November — dried porcinis have a long shelf life and can be found year round. You can even splurge on imported ones (like these Sanniti Italian dried porcinis) without worrying about them spoiling.

Dried mushrooms are prized for their intense flavor, making them an excellent choice for soups and broths (which are similar to au jus). Chefs use them as a flavor bomb in different dishes. In fact, this is one of the best ways to cook with mushrooms. But remember that a little goes a long way. Because the flavor is concentrated, you'll only need a few.

Even though they're dried, the porcinis might still need cleaning. Give them a once-over to inspect for dirt or grit. If they look dirty, a quick brushing or rinse should do the trick before you toss them in your jus. The good news is, since Flay's version is strained at the end, you won't even need to trim the woody stems.