Preheat oven to 400°F. Dissolve Vitamin C powder in water. Separately, whisk together amaranth flour with starch, salt, and ground spices. Mix in Vitamin C solution and oil. Dissolve baking soda in boiling water, and mix into the dough. Sprinkle 6tbsp amaranth flour onto a surface and knead dough for 3minutes. Sprinkle remaining amaranth flour (2tbsp) onto baking sheet. Form dough into a 1" thick circle and place on sheet. Using serrated knife, draw an X on top. Bake at 325°F for 55min or until cooked through.