Slice the preserved lemon wedge into smaller pieces (rind and all). Add it and the remaining dressing ingredients to a non-reactive prep bowl or glass measuring cup.
Blend using an immersion blender or mini food processor. Taste and adjust; correct flavor if necessary. If the dressing is too thick, thin with some half and half.
Cover and refrigerate until ready to use. The salad dressing tastes best if it has had a chance to rest for at least 1 hour but preferably 3 or more hours. After having refrigerated the dressing for most of the day, I tasted it just before serving and adjusted the flavor by adding about 1/2 teaspoon additional sugar.
The dressing was tested on a simple salad of: mixed greens, tomatoes, raw purple asparagus, green cabbage, few sliced raw mushrooms, little bit of fresh mint, cucumbers and carrot shavings. We also tried it as a sauce for freshly steamed vegetables and as a topping for Palestinian musakhan.