To really make your life simple, purchase a two pound, trimmed center-cut tenderloin. The only tenderloin I could find without going to a specialty market was a whole "peeled" tenderloin (meaning the fat has been cut away but it still has the silver skin... which is a pain to remove). Preheat your oven to 425° F. Rub the tenderloin down with some vegetable oil and sprinkle with salt, garlic powder, pepper, and ground thyme. Place on a foil lined roasting pan and roast until a thermometer in the center of the cut reads 140-145° F. Depending on the size of your tenderloin, it can happen fairly quickly... as in less than a half hour. Let the roasted tenderloin cool to room temperature, wrap it tightly in plastic wrap, and then refrigerate until well chilled. Chilling the meat prior to slicing makes life much easier. You want thin slices! Once chilled, slice the tenderloin into approximately 1/8 inch thick slices. The roasting and slicing of the meat can be done up to 3 days ahead of time.
On the day you plan to serve this dish, slice a fresh baguette into 1/4 inch thick slices at a slight angle, so that they slice into longish ovals. Turn on your broiler. Brush or spray (I recommend spraying) both sides of each slice. Lay them out one layer thick on a sheet tray and toast until lightly golden, flip, and toast again on the other side.
Meanwhile, let a package of Boursin cheese (if you have never tried this spreadable cheese, you are missing out!) come to room temperature. Then open a jar of roasted red peppers and slice a bunch of thin strips, about an inch and a half long and 3/8 of an inch thick.
To assemble, spread a small bit of Boursin on the toast. Lay a small piece of sliced tenderloin on the cheese. Add another little spread of cheese on top of the meat and lay two slices of roasted red pepper in an X pattern. That'ts it! These are so yummy! They were one of the more popular dishes I served.
I made 75 of these with about two pounds of tenderloin, 2 baguettes, one decent sized jar (maybe 12 ounce range?) of roasted red peppers, and roughly 8 oz of Boursin cheese.