Holding the asparagus halfway up the stalk, snap off the woody ends at a natural breaking point and discard.

Steam the asparagus spears 3-5 minutes or until they are tender but not limp. Drain and run spears under cold water until completely cooled. Drain well and set aside.

In a large bowl, stir the saffron into the teaspoon of boiling water. Let it stand for 2 minutes or until it is softened. Stir in the vinegar, mustard and sugar. Whisk in the olive oil. Season the mixture with salt and pepper to taste.

Arrange the asparagus on a platter (atop leaf lettuce, if desired) and top with diced pepper. Drizzle vinaigrette over the asparagus. Serve immediately.