Ingredients

• 1/2 cup plus 2 tablespoons red wine vinegar
• 6 tablespoons Dijon mustard
• 1 cup canola oil
• 1 large head of cauliflower, cut into 1-inch florets (about 6 cups)
• 2 cups Kalamata olives, pitted, halved
• 1 1/2 cups chopped celery
• 1 bunch green onions, chopped
• 1/4 cup chopped fresh Italian parsley
• 16 cups arugula (about 10 ounces)

Instructions

1. Whisk vinegar and mustard in small bowl; gradually whisk in oil. Season dressing generously with salt and pepper. Combine cauliflower, olives, and celery in large bowl. Add 3/4 cup dressing; toss to coat. Cover salad and remaining dressing separately; chill overnight.
2. Mix green onions and parsley into salad. Arrange arugula on platter; drizzle with remaining dressing. Top arugula with cauliflower mixture. Sprinkle with pepper.