You won't find another condiment as pretty as this tangy and sweet blackberry mustard.
Bring first 2 ingredients to a boil in a small saucepan over medium-high heat, stirring occasionally and mashing berries with the back of a wooden spoon. Reduce heat to medium, and simmer, stirring often and mashing berries, 2 to 3 minutes or until slightly thickened. Remove from heat, and pour mixture through a fine wire-mesh strainer into a blender, pressing with spoon to release juices; discard solids.
Add honey and next 4 ingredients to blender; process on low 20 seconds. Increase blender speed to high, and process 30 seconds. With blender running, add oil in a slow, steady stream, processing until smooth. Transfer mixture to a small bowl; cover and chill 1 to 12 hours.