Filet Bearnaise with Matchstick Frites
The March issue of Gourmet had a little recipe for steak béarnaise, with fried matchstick potatoes. It was kinda tucked in the middle, among all the other interesting French rustic meals hither and yon. How classic can you get? Meat and béarnaise, with fried potatoes. Steak frites with a twist. Since March, I've probably made this recipe four times. I've made it more than any other idea from that magazine since I got my subscription this year.
Of course, I've personalized it a bit.
My grocery actually had a sale on fillet mignon tonight, which is kismet, as I was going to buy it anyway. Being a grocery instead of a high-end butchery, there was still silverskin and fat all along the fillet, so a bit of cleaning was in order
Then, a little seasoning of kosher salt, cayenne, onion powder, black pepper (semi-coarse), garlic powder, and paprika.
While the steaks sat in the spices, I pulled out the mandolin and cut the potatoes. The last time I tried to cut matchsticks on the mandolin, I shaved off the tips of three fingers. So, I grudgingly used the safety cage. I hate it -- it's noisy and inelegant and awkward...but I kept my blood away from the food this time, so I guess there's a trade-off.
After throwing the matchsticks in a bowl of water (to wash off some starch, and keep them from going gray), I started the base for the béarnaise. 1/4 cup champagne vinegar, 1/4 cup sparkling wine.
Add a chopped shallot and a tablespoon of chopped tarragon
This will reduce until the half-cup or so become about two tablespoons of liquid. Talk about concentrated taste. The steaks, meanwhile, go on the grill.
I started the matchsticks while the steaks were cooking. One potato is pretty much two batches in my beat-up frier with oil set at 350 degrees. Fry until just barely golden, then dust generously with kosher salt. Real pommes frites would be sized somewhere between shoestring fries and steak fries, and would be done in a couple stages -- an initial frying at 250 or so until cooked, then drained and rested until a final fry at 370 or so. But, matchsticks are meant to be crispy, and they're very thin, so only one cooking stage was necessary.
The liquid was reduced at this point, so I took it off as it needs to be room temperature -- or really, cool enough that it won't coagulate egg yolks on contact.
The steaks were done, so off they sit, to rest a bit and reabsorb their juiciness
Time to tackle the béarnaise. The technique is very tricky, and a good judge of how good a foodie-cook one really is. The idea is to warm the vinegar/champagne reduction mixed with the egg yolks until it starts to get almost solid (which becomes basically a savory sabayonne), but it can't hit the stage where it turns into hard-boiled-egg-yolks. There's about a 5F degree temperature range to hit, and stay at, until all the yolk mixture has reached this stage. Then, butter is added as in a beurre blanc, and everything emulsifies into a wonderful, magical thing. It's fun, but also a little nerve wracking. I've never, ever broken a beurre blanc sauce since I learned what it was. However, I've broken a béarnaise twice. The egg yolks add a dimension of heat-control even more fine than what a beurre blanc requires. But if you nail it, you feel like Joe DiMaggio on his wedding night.
First, three egg yolks per the two tablespoons of reduction
Then, I have a larger pan with simmering water in it. I hold the smaller béarnaise pan in the larger water pan and whisk until it hits a stage sort of like mayo and sort of like honey. I can sometimes just do this by sliding on and off a low burner, but the water pan makes the fine control a little easier. After whisking like crazy (the whisking actually puts some air into the béarnaise, which makes things even more delicate and crazy-good), it hits a stage like this:
Now, I've had little, tiny chunks of solidification before, and that can still be salvaged by throwing in chunks of butter immediately and whisking the crap out of any solid pieces. It's not the end of the world and no one will know but you and me. But (I humbly say) I absolutely nailed it this time. So, in goes a stick of butter, a couple tablespoons at a time, whisking away.
When the last tablespoon is in, add a tablespoon of chopped tarragon, and the juice of half a lemon.
Then, steak on the plate, béarnaise over the top, then matchstick frites garnished over everything.