Once rehydrated, dried mushrooms are an easy way to add deeply savory, almost meaty flavor and texture to a dish. But until recently, we didn’t appreciate the wonders they could work for a basic beef roast—if we used them dry.

It’s a trick cooks around the world know well. In Italy, porcini mushrooms ground to a fine powder often are used to add umami richness to fresh pasta and gnocchi. And cooks across East Asia sprinkle finely ground shiitakes into brothy dishes and fried rice as a savory substitute for MSG.

It works because drying mushrooms not only concentrates their flavor, it also changes their flavor composition so they taste even meatier. When dried, the mushrooms take on two new compounds—an aldehyde that mimics the flavor of beef and a ketone that has the same flavor of roasted meat.

Which got us thinking they could be a great way to amp up a beef tenderloin roast, a cut that lacks the fatty richness of other large cuts. Rubbing the roast with black pepper and rosemary helped deliver some of the notes we were looking for, but we suspected mushroom powder easily could take that several notches higher.

To test our theory, we added a handful of finely ground porcinis to our pepper-rosemary spice rub, and we were astonished with the results. The meat tasted deeply rich and, well, even meatier.

We tested several methods for grinding the dried mushrooms and found that a basic spice grinder was the easiest approach most cooks would have ready access to. (When grinding, covering the spice grinder with a damp dishtowel can minimize the inevitable puff of mushroom powder.)

With our beef-boosting rub settled, we focused on rounding out the dish into a one-pan meal fit for a holiday. To double down on the mushroom in the spice rub, we roasted the beef on a V-style rack in a roasting pan over sliced fresh portobellos and onion. Giving the vegetables a head start in a 450°F oven ensured they released excess moisture, enabling them to brown deeply.

Stirring some of the reserved spice rub into the roasted vegetables added complexity, with more fresh rosemary and pungent peppercorns. And a tablespoon of sherry vinegar contributed bright flavor that balanced the roasted richness of the dish.