Preheat oven to 425° F. Cut cauliflower into florets. Peel carrots, cut in half vertically, then cut into 2-inch pieces. Peel turnip and dice into bite-size pieces. Dice onion into bite-size pieces.
In a large bowl toss cauliflower, carrots, turnips and onions with 3 tablespoons of the olive oil and Italian seasoning blend. Place onto a baking sheet and roast for 20 minutes. Remove baking sheet from oven and stir vegetables. Continue baking for 15 minutes or until vegetables are tender.
While vegetables are roasting, make the salad dressing. In a small bowl combine remaining 3 tablespoons of olive oil, rice vinegar, maple syrup, mustard, salt, black pepper and garlic powder.
To assemble the salad combine the lettuce and roasted vegetables, then toss with the dressing. Top with pomegranate seeds and serve immediately