But if you'd like to put on a bit of show, it's perfect. The thing is, beef tenderloin has the least flavor of all cuts of beef. Although also the most tender. So you have to boost the flavor. Roasting outside on a grill is best to impart a smoke flavor. But you hardly roast it at all. It cooks twice. Once to sear it, then again as the outside pastry bakes. And that's where your risk overcooking the beef. The chef protects the beef with another layer of mushrooms and chestnuts and an exceedingly thin layer of prosciutto.
Here, the flavor is boosted with mustard.
He says, "English mustard." Ha!
It is to laugh.
I made my own mustard from ordinary powdered mustard and mustard seeds and it blew my mind. Better than any mustard I've tasted.
Dump an entire tin of mustard powder into a bowl. Don't be shy. Don't hold back. Don't go, "Oh, I'll experiment with half a tin." The WHOLE tin, I said. Go for it.
Dampen the powder with your favorite vinegar until it turns to thick sludge. Too thick to use. The powder will explode with aroma. Like it's been activated. But it will will keep absorbing vinegar. Soon as you get it wet as you like, then it keeps getting thicker and thicker. It takes a long while for it to absorb and you'll end up adding more vinegar than intended.
So at some point stop adding vinegar. Add as much as you'd like your powder to have, then stop. Switch to water. Here your mustard gets diluted, to something more reasonable. It's a balance that you determine.
Any other flavor you add is superfluous, and I'll say, a bit silly.
The mustard plant, and horseradish plant and wasabi plant are all the same family, Brassicaceae, along with all of the cabbages, most are herbaceous plants.
The flavor weakens with time. The seeds, the powder oxidizes and its flavor and nutrition evaporates. Best made in smaller batches that will be used fairly quickly. One tin of powder is a good size. And when you do this, I swear, it will knock your socks off.
Be sure to wear socks so they can be properly knocked off.
There are several other Dijon mustard videos available.