Rinse quinoa thoroughly under cold water, then combine it with water in a saucepan. Bring to a boil, reduce heat to low, cover, and simmer for 15 minutes until liquid is absorbed.

Heat olive oil in a skillet over medium-low heat. Add sliced onions and salt, cooking slowly for 20-25 minutes until golden brown. Stir in sage before removing from heat.

Preheat oven to 400°F. Peel and cube butternut squash. Toss with olive oil and salt, spread onto a baking sheet, and roast for about 30 minutes until tender.

In a bowl, combine remaining olive oil with lemon juice. Whisk together, then add cranberries to soak slightly.

In a bowl, combine warm quinoa with caramelized onions, roasted squash, and spinach. Pour dressing over and toss gently until spinach is wilted.

Sprinkle salted cashews on top before serving. Adjust seasoning if necessary.