We received the recipe for these great-tasting appetizers from Susan Wambui Thiong'o in Nairobi, Kenya, in 2004. You can substitute peppery arugula for the watercress, if you prefer.
2/3 cup fat-free sour cream
1/4 cup Dijon mustard
2 tablespoons minced fresh tarragon
2 tablespoons prepared horseradish
1 (1 1/2-pound) beef tenderloin, trimmed
1/2 teaspoon freshly ground black pepper
2 tablespoons fresh lemon juice
3 cups trimmed watercress (about 1 bunch)
1 (8-ounce) French bread baguette, cut diagonally into 16 slices
2 tablespoons capers
1/2 cup (2 ounces) shaved fresh Parmesan cheese
How to Make It
Combine first 4 ingredients, stirring well with a whisk. Cover and chill.
Secure beef at 2-inch intervals with twine. Sprinkle beef with pepper. Heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Add beef to pan; cook 15 minutes or until desired degree of doneness, turning frequently. Let stand 15 minutes. Cut into 16 slices. Sprinkle with juice.
Arrange watercress evenly on bread slices. Place 1 beef slice and about 1 tablespoon chilled sauce over each bread slice. Arrange capers and cheese evenly over sauce.