- 1/3 cup mayonnaise
- 1/3 cup sour cream
- 3 tablespoons drained bottled horseradish
- 1 teaspoon red- or white-wine vinegar
- 1/4 teaspoon fresh-ground black pepper
- 3/4 teaspoon salt
- 1 large head escarole, torn into bite-size pieces
- 1/4 pound mushrooms, sliced thin
- 1 small red onion, sliced thin
- 1/2 pound sliced roast beef, cut into approximately 1 1/2-by-1/2-inch strips
- In a medium glass or stainless-steel bowl, whisk together the mayonnaise, sour cream, horseradish, vinegar, pepper, and 1/2 teaspoon of the salt until smooth.
- In a large bowl, toss the escarole with the mushrooms, onion, roast beef, the remaining 1/4 teaspoon salt, and all but 2 tablespoons of the dressing. Serve the salad with the remaining dressing drizzled over the top.