Preheat the oven to 400F. Grease an 8x10 inch roasting pan with a tablespoon or so of the olive oil.
Put the potato wedges and garlic in a large pot with water to cover, salt it, and turn the heat to high. When the water begins to boil, stir in the quinoa. Adjust the heat so that the water boils assertively and cook, stirring once or twice, for about 5 minutes.
Drain the quinoa, garlic, and potatoes in a strainer, but leave them fairly wet. Spread them into the prepared pan, sprinkle with salt and pepper, drizzle with the remaining olive oil, and gently toss with a spatula. Spread them out again. Roast, undisturbed, for 15 minutes. Gently toss again, scraping up any browned bits from the bottom of the pan, and return the pan to the oven for another 10 minutes or so, until the potatoes are tender on the inside and golden on the outside.
Add the scallion, bell pepper, chile and toss everything one last time. Taste and adjust the seasoning, keeping in mind. That the cheeses will add some saltiness. Spread the cheese over all and return to the oven for another 5-8 minutes, until the cheese is melted and bubbling. Sprinkle with parsley and serve.