Put the apple pieces, onion pieces and the garlic pieces in a blender, add the mustard, salt, pepper, Worcestershire sauce, lemon juice and half of the vinegar. Puree everything finely, then mix in the oil and the remaining vinegar alternately, add the chives, season a little with salt and pepper if necessary.
Fill into a bottle for storage and refrigerate. The sauce will last 2 weeks if you put it in a cool place.