Preheat the oven to 350 degrees F.
Arrange the bread slices on 2 heavy large baking sheets. Brush 3 tablespoons of oil over the bread slices. Bake until the crostini are pale golden and crisp, about 15 minutes.
Wrap 1 curly endive and 1 slice of cheese with 1 slice of prosciutto, allowing the tops to extend 1-inch over 1 long side of the prosciutto. Arrange the crostini on a platter. Top each crostini with a prosciutto roll. Drizzle the vinaigrette over and serve.
Mix the vinegar, lemon juice, honey, salt, and pepper in a blender. With the machine running, gradually blend in the oil. Season the vinaigrette, to taste, with more salt and pepper, if desired.
Yield: 1 3/4 cups