This is one of those recipes you'll pull out again and again. . . until you memorize it. (it's really that simple.) Serve this pilaf instead of rice, potatoes, or any other starchy side.
Heat oil in a large saucepan over medium-high heat. Add onion and garlic, and cook, stirring often until the onion is starting to brown, 5 to 7 minutes. Add broth and salt and bring to a simmer. Add quinoa, and return to a simmer. Cover, reduce heat to low to maintain a gentle simmer and cook, undisturbed until the liquid has been absorbed and the quinoa is tender, about 15 minutes.
Place peas in a sieve or strainer and run water over them to thaw. Stir peas into the quinoa, and let sit off heat until the peas are heated through, about 1 minute.