Ready in 20 minutes
This is a popular appetizer of mine that I enjoy making for get togethers. It comes from a favorite cookbook of mine titled "Party Appetizers." It is a classic and one that few dressy parties should be without. The meat can be grilled outdoors if it's a summer party, then sliced and served on the toasts right there. Guests love to smell it cooking !
To make the horseradish cream: In a small bowl, stir together the sour cream and horseradish and season to taste with salt and pepper. Cover and refrigerate the mixture until ready to use (up to 1/2 hour).
Preheat a broiler and adjust the rack so it is about 4 inches from the heating element. Brush both sides of the bread slices with oil and broil, turning once, until they are golden. Keep the broiler on. Season the steaks on both sides with salt and pepper to taste, then broil them until medium-rare, 4 to 6 minutes per side. Remove the steaks and let them stand for at least 5 minutes or up to 1/2 hour before slicing.
To serve, slice the meat across the grain into 24 thin slices about the length of the bread pieces. Spread 1 side of each baguette slice thickly with the horseradish cream. Pinch the leaves off the watercress sprigs, place a few leaves on each slice, then top with slices of filet mignon.