Start by heating a large skillet over medium heat. Add the olive oil and let it warm up for about a minute. As the oil heats, the enticing aroma will begin to fill your kitchen.
Add the chopped onion and sauté it for about three minutes until it's translucent and fragrant. This will lay the groundwork for a flavor-packed dish.
Next, stir in the minced garlic and sauté for an additional minute, being careful not to let it burn. You want that beautiful golden color without the bitterness.
Now, introduce the butternut squash cubes to the skillet, along with the nutmeg, salt, and pepper. Cover and stir occasionally for about eight minutes. The squash should become tender but not mushy.
After eight minutes, uncover the skillet and add the minced sage, cooking for an additional minute. This will infuse the oil and squash with an aromatic flavor.
Pour in the vegetable broth and bring the mixture to a boil. Don't rush this step; it allows the flavors to meld together beautifully.
Once boiling, reduce the heat and let the squash simmer uncovered for about twenty minutes. You’ll know it’s done when the squash is soft and the broth has reduced by half.
While the squash is simmering away, bring a large pot of salted water to a boil. Add the spaghetti and cook it according to the package directions until al dente. Once ready, drain it and set aside.
Once the squash mixture is ready and cool enough to handle, transfer it to a food processor or blender. Purée it until smooth, adding extra vegetable broth or water if needed to achieve your desired sauce consistency.
Finally, return the puréed sauce to the skillet and toss in the drained spaghetti and spiralized zucchini. Cook everything together over medium heat for about two minutes, ensuring all components are well combined. Season with additional salt, pepper, and sage before serving.
