Preheat the oven to 425°F and line a baking sheet with parchment paper.

Drizzle the squash with olive oil, sprinkle with salt and pepper, and place cut side down on the baking sheet. Wrap the shallots and garlic cloves in foil with a drizzle of olive oil and a pinch of salt and place on the baking sheet. Roast for 30 minutes, or until the squash is soft.

Measure 1 cup of the roasted squash flesh and transfer to a blender with the shallot, peeled garlic, water, cashews, olive oil, nutritional yeast, vinegar, sage, thyme, ¾ teaspoon salt, and several grinds of pepper. Blend until creamy.

Cook the pasta according to package directions in a pot of salted boiling water. Reserve 1 cup of the hot pasta water.

Drain the pasta and return to the pot. Stir in the sauce, adding ½ to 1 cup of the reserved pasta water to loosen the sauce and coat the pasta. Season with ¼ to ½ teaspoon salt. Top with freshly ground black pepper, a few thyme leaves and sautéed broccoli, if desired.