1. Cook quinoa according to package directions.
2. While quinoa cooks, heat 1 tablespoon oil over medium-high heat in a large, heavy-bottomed skillet. Saute the squash, stirring often, until it is tender and lightly browned (15-20 minutes).
3. Season to taste with salt and pepper and transfer to a bowl. Turn the heat down to medium and add the remaining oil and the onion. Cook, stirring often, until the onion begins to soften (4-5 minutes).
4. Add celery and thyme. Cook, stirring often, until celery is just tender (3-4 minutes). Add the garlic and cook until fragrant (30 seconds). Transfer to the bowl with the squash.
5. Add the quinoa and remaining ingredients and stir together. Season to taste with pepper. Reheat in a casserole dish in oven, if needed, to serve warm.