Cut 1 slender baguette (1/2 lb.) in half, slice each half lengthwise, and place, cut side up, on a 12- by 15-in. baking sheet. Broil about 3 in. from heat until toasted, 2 to 3 minutes.
Meanwhile, mix 1/2 cup diagonally sliced green onions, 1/2 cup mayonnaise, and 1/2 cup grated or finely shredded parmesan cheese.
Spread mixture on bread. Return to broiler and broil until lightly browned, about 1½ minutes. Let cool about 2 minutes to crisp. Cut each piece in thirds.
Time: 15 minutes