Place a rack in the center of your oven and preheat the oven to 400 degrees F. Place the red onion in a small bowl and cover with water. Set aside. (This keeps the onion’s flavor but helps soften its harsh bite…and endless onion aftertaste.)
Place the butternut squash in the center of a large rimmed baking sheet. Drizzle with olive oil and maple syrup, then sprinkle with 1 teaspoon salt and 1/2 teaspoon pepper. Toss to evenly coat, then spread the squash into a single layer. Bake for 15 to 20 minutes, turning once, until tender. Remove from the oven and set aside.
While the squash is baking, bring the broth (or water) and quinoa to a boil in a medium pan. If you are using water, add 1/4 teaspoon kosher salt. Once boiling, reduce the heat to a simmer, cover, and let cook 15 minutes, until the water is absorbed. Remove from the heat and let stand with the lid on for 5 minutes. Fluff with a fork, then transfer to a large serving bowl.
In a small bowl or large measuring cup (or a mason jar with a tight-fitting lid), combine the dressing ingredients: olive oil, vinegar, mustard, maple syrup, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Drizzle enough of the dressing over the warm quinoa to moisten it, then stir to combine.
Scrape the roasted butternut squash and any pan juices into the bowl with the quinoa. Add the cranberries, pepitas, and thyme. Drain the red onion then add it to the bowl. Toss to combine, adding more dressing as desired. (I like to reserve a little of the dressing for adding to leftovers.) Serve warm or at room temperature.
You can enjoy this salad on its own or try mixing it with arugula or spinach for an extra serving of greens. For the sake of streamlining the ingredients, I omitted the cheese, but if you feel so called, feta, goat cheese, or even a mild blue cheese such as gorgonzola would be delightful additions too.
No butternut squash? Try swapping diced, cubed sweet potatoes (note that they may need a little longer in the oven to roast).
Store leftovers in an airtight container in the refrigerator for up to 4 days.