Ingredients

1 cup champagne vinegar 

1 teaspoon Spanish saffron 

1/2 medium red onion, finely chopped 

2 tablespoons Dijon mustard 

1 tablespoon sugar 

Zest and juice of 1 lemon 

1 cup extra-virgin olive oil 

Coarse salt and freshly ground pepper 

Preparation

In a small saucepan, combine vinegar, saffron, and onion, and bring to a boil. Cook over high heat until reduced to one-third of the original volume. Remove from heat, and stir in mustard, sugar, and lemon zest and juice. Place mixture in the bowl of a food processor or blender, and, with the motor running, slowly drizzle in oil until mixture is emulsified. Season with salt and pepper.