Roasted Cauliflower Hazelnut Salad

head cauliflower, broken into small florets

extra-virgin olive oil, divided

hazelnuts, with skins

sherry vinegar

maple syrup

Generous ¼ teaspoon ground cinnamon

Generous ¼ teaspoon ground allspice

pomegranate seeds

large celery stalk, cut on an angle into ¼-inch slices

flat leaf parsley leaves

Sea salt and freshly ground black pepper