Place cauliflower, cut side down, in a large baking dish. Pour olive oil evenly over cauliflower and use your hands to rub the oil and salt mixture into the cauliflower.
Place on the middle oven rack, and roast 1 hour (if cauliflower starts getting too dark, then cover with aluminum foil).
While cauliflower is roasting, whisk together all the vinaigrette ingredients in a small bowl.
When cauliflower is finished roasting, pour vinaigrette evenly over entire head.
To serve, cut whole cauliflower in half, then cut each half into 4 pieces.
Notes
Excerpt from The Diabetes Cookbook published by American Diabetes Association.