Our Christmas 2024 dinner choices are in the semifinal stages. The #1 ranked choice today for a main protein is… steak. I cook a lot of it in summer and fall, so mostly know what I’ m doing there.
So, I ask here for recommendation for a special-occasion sauce.
If it makes a difference, the salad winner is a roasted hearts of Romaine with hazelnuts and gorgonzola dressing. Other sides YTBD.
Au poivre or béarnaise.
I can never look past béarnaise on the rare occasions I eat steak. It’s a classic for a reason.
Although I’m equally happy with no sauce, but a dollop of Dijon on the plate.
Cognac cream sauce
Mushrooms & sherry with a LOT of butter.
As much as I love mushroom cream sauce for steak, since your salad is going to have a rich, creamy dressing, I’d go with a bright chimichurri or similar for the steak. Or a red wine and sherry reduction, mounted with butter.
Compound butter.
Pureed kimchi (Or as some people call it “K-1 steak sauce “)
Horseradish cream.
Salsa verde
Bearnaise or sauce choron
So many choices! I personally go without, having seasoned the steaks with mashed garlic, black pepper, dry mustard powder and a bit of salt. Chanterelle and red wine reduction, maybe.
Ooh, yes! Chimichurri would be great, too.
I love a nice mushroom cream sauce with steak, but it’s def on the richer side.
It also really depends on the steak that’s being served. I don’t need any sauce for a fatty rib-eye, but something super-lean like sirloin/tenderloin/filet mignon? Hell yeah.
I like the horseradish cream/sauce idea, too. Maybe the ‘steak’ being served is prime rib? 
Beef or veal stock (or some demi glace), shallots, wine, blob of Dijon, and then mount with bone marrow. Parsley or another green herb of choice to garnish.
Also, +1 for chimichurri.
There was a link to a finished product on eGullet - http://forums.egullet.org/index.php/topic/53228-les-halles-cookbook-by-anthony-bourdain/page__st__210__p__1886901#entry1886901
I second the Sauce au Poivres, I love sharpness Pepper and Cognac with the rich smoothness of the Cream.
Madeira Sauce is also up there for me Truffle enriched is even nicer (or better yet the whole or Rossini Prep). 
Sauce Marchand du Vin, hands down. And use the same wine you are going to drink.
This recommendation comes with a history. The first meal I cooked for my college girlfriend was a tremendous splurge for a graduate student. The wine was a classed growth Margaux, recommended by the wine merchant for the fillet mignon. I used a third of the bottle for the SMdV. We’ve been married over fifty years.
Bearnaise or compound butter get my vote. I mean, one can always just throw some red wine into the pan drippings and fond and reduce. Throw in cold butter to get it nice ‘n glossy and voila.
Yum. I had this on a cauliflower steak at The Loyal (RIP) in Greenwich Village.
At special occasions we had steak sauce made with foie gras (similar to this recipe)
Hard to argue with that success!
I was thinking Marchand du Vin as well. One of the first serious sauces I made. I don’t like beef so much, so I haven’t done steak in forever, but the sauce is fantastic.
Serious question, no snark.
But why do you need a sauce for the steak?
Because a sauce is nice to have with most things, including a steak. Although, as I wrote upthread, I’m also happy just to have mustard
