Preheat the oven to 350°F. Arrange the hazelnuts in a single layer on a small rimmed baking sheet and toast until browned and fragrant, stirring occasionally, about 10-12 minutes. Remove loose skins and chop roughly.

Increase oven heat to 400°F. In a large mixing bowl, toss the carrots with 2 tablespoons olive oil and salt and pepper until evenly coated. Arrange them in a single layer on a large baking sheet lined with parchment paper and roast for 25-28 minutes or until tender, turning halfway through. Let cool slightly.

Meanwhile, in a food processor, combine the hazelnuts, herbs, garlic, lemon zest, and cumin. Pulse until the hazelnuts are finely chopped, the herbs are minced, and the mixture is just combined. Transfer to a bowl. Stir in the lemon juice and ¼ cup oil to make a thick paste. Season with salt, to taste.

Transfer the carrots to a platter and top with the gremolata. Serve immediately.