Preheat the oven to 450 degrees F.
In a small bowl, add the dressing, horseradish, and italian seasoning and stir until well blended.
In a large bowl, toss the vegetables with half of the dressing and season with freshly ground pepper. Roast the vegetables on a parchment lined baking sheet for 15 to 20 minutes or until golden. Remove from the oven and let cool slightly.
In another bowl, toss the remaining dressing with both the spinach and romaine until well coated.
Arrange the salad on a serving plate or platter and top with the roasted vegetables and serve immediately.