Quinoa, Mushroom, and Spinach Salad

3/4 cup quinoa 1 1/4 cups water Salt to taste 1 bag baby spinach, rinsed and dried, or 1/2 bunch spinach, stemmed, washed and dried 6 white or cremini mushrooms, sliced 1/4 cup chopped walnuts 2 tablespoons chopped fresh parsley 1 ounce feta cheese, crumbled (1/4 cup, optional) For the dressing: 1 tablespoon freshly squeezed lemon juice 1 tablespoon sherry vinegar 1 teaspoon Dijon mustard 1 small garlic clove, puréed Salt to taste 2 tablespoons extra virgin olive oil 1/3 cup buttermilk Freshly ground pepper 1. Place the quinoa in a strainer and rinse several times with cold water. Place in a medium saucepan with 1 1/4 cups water and salt to taste. Bring to a boil, cover and simmer 15 minutes, until the grains display a threadlike spiral and the water is absorbed. Remove from the heat, remove the lid and place a dish towel over the pan, then return the lid to the pan and let sit for 10 minutes or longer undisturbed. Transfer to a salad bowl and fluff with forks. Allow to cool. 2. Add the spinach, mushrooms, walnuts, parsley and optional cheese to the bowl. Whisk together the dressing ingredients and toss with the salad just before serving