Preheat the oven to 425 degrees F. Lightly coat a baking sheet with cooking spray.
In a large bowl, combine the cauliflower florets and shallot pieces. Add 1 tablespoon olive oil, smoked paprika, rosemary, ¼ teaspoon salt and peppers. Toss gently to coat. Transfer to the prepared baking sheet.
Roast the vegetables until the cauliflower is tender, turning halfway through, 20 to 25 minutes total.
Let the vegetables cool slightly, cut the roots off of the shallot pieces and transfer to a food processor.
While the vegetables are roasting, lightly toast the hazelnuts in a small skillet set over medium heat. Stir frequently and keep an eye on the nuts so they don’t burn.
Add 2 tablespoons of the hazelnuts to the vegetable in the food processor, along with the remaining ⅛ teaspoon salt. Puree the mixture until almost smooth.
With the food processor running, drizzle in the remaining 3 tablespoons olive oil.
Transfer the dip to a serving bowl, garnish with a drizzle of olive oil (if desired) and parsley. Serve with raw vegetables, pita triangles or tortilla chips.