In a small saucepan, bring water to a boil. Add quinoa. Reduce heat; simmer, covered, until water is absorbed, 12-15 minutes. , Meanwhile, in a large saucepan, heat oil over medium-high heat; saute onion until tender. Stir in peas and broth; bring to a boil. Reduce heat; simmer, uncovered, until peas are tender, about 5 minutes., Puree soup using an immersion blender. Or cool slightly and puree soup in a blender; return to pan. Stir in quinoa, salt and pepper; heat through. Serve with toppings as desired.