Preheat the oven to 400 degrees F. Halve and seed the spaghetti squash; roast, then scrape into strands (see Cook's Note).
Meanwhile, toast the hazelnuts in a dry skillet over medium-high heat, stirring occasionally, about 3 minutes. Transfer to a plate and let cool.
Pulse the kale, parsley, garlic, raisins and 2 tablespoons of the toasted nuts in a blender or food processor until combined. Add 1/4 cup olive oil; blend until smooth. Add 1/3 cup water, the parmesan, Worcestershire sauce, 1/2 teaspoon salt and a few grinds of pepper. Pulse until the pesto comes together, adding up to 3 more tablespoons water to loosen, if necessary; season with more salt and pepper.
Heat the remaining 1 tablespoon olive oil in a large skillet over medium-high heat. Add the spaghetti squash and cook, stirring, until coated. Add 3/4 cup of the kale pesto. Stir to coat, adding up to 1/2 cup water to loosen; season with salt and pepper. Top the squash with the remaining toasted nuts and more parmesan.
How to Roast Spaghetti Squash Trim both ends with a chef's knife, then position the squash upright and halve lengthwise. Scoop out the seeds with a spoon and discard. Place the squash halves cut-side down on a baking sheet. Roast at 400 degrees F until tender, 25 minutes; let cool slightly, Scrape the squash into strands with a fork. Discard the skin. Cook's Note: Refrigerate the extra pesto up to 1 week or freeze up to 1 month.
Recipe courtesy of Food Network Magazine