Greens Pie with Millet Amaranth Crust

Name: Greens Pie with Millet Amaranth Crust
Ingredients: 3/4 cup millet; 3/4 cup cup amaranth; 4 cups vegetable stock; 1 tablespoon neutral-flavored oil; 1 small red onion (chopped (about 1 cup)); 2 cloves garlic (minced); 10 ounces white button or crimini mushrooms (sliced); 3 carrots (chopped); 1 14 ounce can cannellini beans (drained and rinsed); 1 large bunch Swiss chard (stems removed, chopped (about 6 cups)); 1 large bunch Kale (stems removed, chopped (about 6 cups)); 1 cup vegetable stock; 2 tablespoons rice vinegar; 2 tablespoons tamari; 1 tablespoon arrowroot; 2 tablespoons fresh parsley (chopped, for serving)