1 ripe avocado
1 Tablespoon fresh lemon juice
1 Tablespoon minced fresh chives
1/2 teaspoon salt
1/8 teaspoon pepper
2 Tablespoons mayo
1/2 lb thinly sliced rare roast beef
Mash avocado and add lemon juice, chives, salt, pepper and mayo. Spread avocado mixture over one side of each roll. Top with roast beef and arugula.