Once boiling, lower the heat and allow to simmer, covered, until the liquid is absorbed by the quinoa (approx. 10 minutes). Don't overcook! Place the saucepan with cooked quinoa to the side.
Once the butter is melted, add the frozen peas and corn (no need to defrost). Over medium heat, saute the corn and peas for about 5 minutes until cooked. Make a well in the skillet by pushing the corn and peas to the side. Add the minced garlic. Saute until fragrant (about a minute). Combine the garlic, peas, and corn in the skillet. Add the diced green onions, cooking for two minutes. Remove from the heat.
Spoon the cooked quinoa into the peas and corn mixture. Combine ingredients in the pan. Season with salt to taste, and if desired add an extra TB butter.