Heat oil in large saucepan or Dutch oven over medium heat. Add onions, carrots and celery and sauté until just tender (5-8 minutes). Add garlic and stir for 2 minutes. Add tomato paste and combine with other ingredients. Add stock and simmer ~20 minutes. Add beans and quinoa, cover and simmer until quinoa is cooked (tiny threads are visible), approximately 20 minutes. Remove lid, stir in slivered greens and cook an additional 5-8 minutes.
Season with salt and pepper. Serve with a splash of sherry vinegar
Note: We found that this recipe could accommodate 1 1/2 - 2 cans of white beans which may also require some adjustment on the amount of stock. We started with 6 cups and when reheating leftovers, added 1/2 cup more.