- 2 cups 1/2-inch cubes cooked steak (about 1 pound)
- 2 tablespoons drained capers
- 2 tablespoons chopped cornichons or gherkin pickles
- 2 tablespoons minced red onion
- 1 tablespoon Dijon mustard
- 5 tablespoons mayonnaise
- 8 1/2-inch-thick slices olive or rosemary country-style bread (each about 3×5 inches)
- 8 large tomato slices
- 2 small bunches arugula, trimmed
- Combine cooked steak, capers, cornichons, red onion, Dijon mustard, and 2 tablespoons mayonnaise in medium bowl; toss to blend. Season salad with salt and pepper. (Can be prepared 6 hours ahead. Cover and refrigerate.)
- Arrange bread on work surface. Spread slices with remaining 3 tablespoons mayonnaise. Divide steak salad among 4 bread slices. Top salad on each with 2 tomato slices and 1/4 of arugula. Press second bread slice, mayonnaise side down, onto each sandwich. Cut sandwiches diagonally in half and serve.