Pre-heat the oven to 400°F.
Halve the squash lengthwise and place cut-side down on baking sheets. Roast for about 1 hour or until tender, then turn cut-side up and shred the squash into spaghetti-like strands with the tines of a fork; season with salt and pepper.
Defrost the spinach and place in a clean kitchen towel. Wring out all the liquid, then separate the spinach with your fingertips to loosen it up.
Toast the walnuts in the oven or a small pan until fragrant and crispy-brown at the edges; cool.
Place the stock in a food processor or blender and add the spinach, parsley, shallot, garlic and toasted walnuts. Pulse into the pesto sauce.
Heat the olive oil, four turns of the pan, in a large skillet over medium heat; add the pesto and stir for 2-3 minutes to warm and combine the flavors. Season the sauce with salt, pepper and nutmeg.
Add the pasta or gnocchi and some of the starchy cooking water to the pan to combine or toss with the roasted spaghetti squash right in squash shell. Combine some Parmigiano Reggiano cheese, a small handful at a time, into the squash, to taste; serve warm.
This is one of many “Yum-o!” recipes – it’s good and good for you. To find out more about Yum-o!, Rachael’s nonprofit organization, visit