Step 1

Heat the oven to 450°F with a rack in the upper-middle position. Line a rimmed baking sheet with kitchen parchment. In a large bowl, toss the cauliflower, ¼ cup of the oil and ½ teaspoon each salt and pepper. Sprinkle with the breadcrumbs and 1 cup of the Parmesan; toss well. Distribute in an even layer on the prepared baking sheet, then sprinkle on any breadcrumb-cheese mixture remaining in the bowl. Roast until a skewer inserted into the largest florets meets just a little resistance, 15 to 20 minutes. Meanwhile, wipe out the bowl. In it, combine the onion, lemon juice and ¼ teaspoon salt; set aside.

Step 2

When the cauliflower is almost fully tender, remove the baking sheet from the oven. Using a wide metal spatula, scrape up and flip the cauliflower, then redistribute in an even layer. Sprinkle on the hazelnuts and half (¼ cup) of the remaining Parmesan. Continue to roast until the cheese is nicely browned, 8 to 10 minutes.

Step 3

Meanwhile, add the remaining ¼ cup oil and remaining ¼ cup Parmesan to the bowl with the onion. Using a fork, stir to combine. Add the kale, toss until evenly coated and let stand for 10 minutes to allow the kale to soften slightly.

Step 4

Using tongs, transfer the still-warm cauliflower florets to the kale mixture, leaving the bits of nuts and cheese on the baking sheet. Toss, then taste and season with salt and pepper. Transfer the salad to a platter and sprinkle with the bits remaining on the baking sheet.