- 1 cup mayonnaise
- 1/2 cup sour cream
- 3 tablespoons prepared horseradish, drained
- 3 tablespoons olive oil
- 1/2 teaspoon salt
- 1/2 teaspoon black pepper
- 1 (32-ounce) package cut romaine lettuce or 2 medium heads romaine lettuce, cut into bite-sized pieces
- 1 pound thick-sliced roast beef, cut into 1/2-inch strips
- 1/2 medium-sized red onion, sliced (about 1/2 cup)
- 2 medium tomatoes, chopped
- 2 cups seasoned croutons
- In a medium bowl, combine mayonnaise, sour cream, horseradish, olive oil, salt, and pepper; mix well and set aside.
- Place remaining ingredients, except croutons, in a large bowl; toss to combine. Pour dressing over salad and toss to coat well. Stir in croutons, and serve.