Beef tenderloin baguettes w/ mustard horseradish sauce. 1 1/2-pound beef tenderloin, trim the fat 3 1/2 Tbs. extra-virgin olive oil 1 large bunch arugula, trimmed 1 4-ounce jar capers, drained 1/2 C. shaved Parmesan cheese 2 Tbs. fresh lemon juice 1 French-bread baguette, sliced diagonally into thin slices Mustard-Horseradish Sauce 2/3 C. sour cream 1/4 C. Lemon Dill Dijon mustard 2 Tbs. olive oil 2 Tbs. prepared white horseradish In a small bowl combine the sour cream, Dijon mustard, olive oil, and horseradish, blend until creamy, season with salt and pepper to taste. You can make the sauce one day ahead, just cover and chill. Sprinkle the tenderloin with salt and pepper. Add one tablespoon of olive oil to a large heavy-duty saute pan, heat to medium-high heat. Add the tenderloin and sear until brown on all sides, then cook it to your tastes, about 20 minutes for medium-rare. Transfer beef to plate, cover with foil and refrigerate until cool. Using a large sharp knife cut the tenderloin crosswise into very thin slices. Cover a large decorative platter with arugula and arrange the beef slices on top. Combine 2 1/2 tablespoons oil and lemon juice and drizzle over the beef. Sprinkle the capers and Parmesan cheese on top. Have the slices of bread on a separate platter and have guests use tongs or a serving fork to put the arugula and beef onto the bread and then drizzle with the mustard horseradish sauce.