Just about every restaurant that sells beef will have a preparation of fillet. I guess most American diners expect it, because the tender texture of it symbolizes the ultimate in luxury. I mean, you barely have to have teeth to be able to chew it, right? There’s one little problem, though: fillet really doesn’t taste like ANYTHING. Think back to all the times you’ve had fillet mignon; you’ve almost always had it with some sort of sauce. For the home cook, this opens up a lot of possibilities. You need only look at either Julia Child or Jacques Pepin books or websites to get some ideas for sauces. Your best bet here is to consider what wine you want to serve and to try and find something that at least doesn’t get in its way.
The classic mother sauces for haute cuisine are roux thickened:
bechamel (white roux diluted with milk)
veloute (white roux diluted with stock). Allemande is a thickened version of veloute.
espagnole (dark roux diluted with beef/veal stock with tomato sauce or paste)
While all of these have their place, this is not where I’d go for fillet. Stick with a flavored emulsion sauce. Classically, this would be something like Hollandaise (egg yolks emulsified with butter) or Bernaise (Hollandaise with reduction of white wine vinegar, shallot, and herbs). Either of those would work just fine, and you’d love it. If you want to mix it up though, think of the flavors that go well with beef: red wine, butter, black pepper, balsamic vinegar, black truffle, foie gras, salt, cognac, heavy cream, bacon, onion/shallot, etc. You can make a “gravy” for your meat that has a ton of flavor and would complement your meat/wine selection.
All you have to do is make an emulsion that has the consistency and flavors that you want. Remember that an emulsion is mixing two normally unmixable liquids by suspending one in another, in this case suspending fat in a flavored liquid. In my case I had some beef stock, red wine, and black truffles.
The beef stock I combined with red wine about 4:1 (but you could do more or less) and chopped up the truffles as finely as I could. Reduced in a sauce pan to about 1/3 of original volume or until it was just starting to thicken up a bit. I then started adding fat (ideally you would do this with clarified butter, but I just used regular stick butter) and whisking it in until the sauce came together or emulsified. At this point, you just keep tasting and testing the sauce until the salinity and the texture are what you want. Problems?Too salty – If you used salted stock or broth, you have to be really careful here because the more you reduce, the saltier it will be. You have a couple of options. Use a thickener like arrowroot, corn starch, or xanthan gum. Use the latter if you need it to stay clear. Corn starch will probably make it the cloudiest. These are essentially flavorless and will thicken a stock or sauce if you need it. Another option is lower the salt in the meat seasoning, and let the sauce be that component. Too thin- reduce more prior to adding butter. If not, you can still boil it down, but it’s likely to be cloudy. Clear sauce is just a style point. Alternatively, you may need to add more fat, typically butter.
Too thick – thin with more stock, water, wine, or cream. Broken – add more liquid, then re-emulsify.
Preparing the meat
For price purposes, I can’t think of why you wouldn’t buy the whole tenderloin and cut it up. If you get cable, try and find Alton Brown’s Good Eats Tender is the Loin 1 for tips on how to break down. You can also check out this video, there’s just not much description. The key is to not throw away the scraps. You can save those, sear them and throw them into a sauce to get some extra flavor. Alternatively, if the meat is lean enough you could treat it just like you would the fillet.
Because the sauce is going to be the star, I take a minimalist approach to seasoning the meat. A little vegetable or olive oil, followed by coarse salt and black pepper. That’s it. This is a meat you don’t want to overcook. The higher the temperature (think ceramic grill), the more likely you’ll get the crust on the outside, and uniform temperature internally. I personally don’t like fillet if the finishing temperature is much over 130-135. Remember that the meat (1) should rest for 10 minutes or so and (2) that the temperature may increase by about 10 degrees as it does so. I’ll typically just use an instant read thermometer and pull it off just before it reaches 120. DO NOT COVER! This will cause it to steam and overcook. Ideally, place on a raised rack, otherwise the juices coming from the bottom will steam, leaving it uneven.
Once it’s rested, slice to desired thickness and serve with your sauce. In fact, throw the resting juices that came out of the meat back into your sauce and adjust if needed.