This is an updated version of James Beard's "cocktail hamburgers." You can marinate the beef two days before the party and mix the horseradish cream the day before. Assemble sandwiches, as we have; or have the beef on a platter, the rolls in a basket, and the horseradish cream in a bowl, and let your guests make their own.
I made these for Super Bowl - nice 'party' entree. I didn't use this sauce recipe but one from Bon Appetit 1999 12. I bought the tenderloin at Costco and it was in two 2-inch thick pieces (about 1.25#) for four of us after lots of apps we only used one piece. I marinated longer than called for and am not sure there was a lot of flavor from the marinade - leftovers will tell. I roasted the meat (standing up) @450º on convection for about 15 minutes and it was medium rare to rarish - perfect!
This is a great party dish - I've made it a few times. The marinade is great as directed, as is the suggested cooking time (if you like your tenderloin medium rare, which I do). My one word of caution is that, with a 2.5 lb tenderloin, you won't really have enough meat for 30 sandwiches. My tenderloin was closer to 2.25 pounds, and I yielded about 25 sandwiches, but the general consensus was that they could use a little more meat. So, I'd definitely expect fewer (but more satisfying) sandwiches next time.
I also made this as a main dish. It is outstanding, wrapped with apple smoked bacon and grilled on a 700 degree griddle till med/rare. I also made the sauce but I used whole milk sour cream.
