In a medium nonreactive saucepan, combine all of the ingredients except the mustard, salt and pepper. Add 1 1/2 cups of water and simmer over moderately high heat until the apricots are soft, about 15 minutes. remove from the heat and let cool.
Transfer the contents of the saucepan to a blender and puree until smooth. Strain the puree through a fine-meshed sieve into a bowl and stir in the mustard. Season with salt and black pepper. Thin the mustard with water if it seems too thick. Let cool, then transfer the mustard to a glass jar and refrigerate for up to 1 week.