The toasty combo of quinoa, walnuts, oregano and goat cheese, with a sauce made from dried ancho chiles, fills mid-size poblano peppers.
Roast poblanos over gas flame or under broiler, until blackened, turning as needed. Transfer to a bowl, cover tightly with plastic, and let steam until cool enough to handle, 10 to 15 minutes. Peel peppers. With stems intact, slit each pepper lengthwise on one side only. Open slightly; remove all seeds, keeping pepper as intact as possible. Reserve peppers.
Bring stock to a boil in medium saucepan, add quinoa, stir well, and reduce heat to a simmer. Cover and cook until stock has absorbed, 12 to 16 minutes. Set aside to cool.
Heat oil in medium skillet over medium-low heat. Add carrots and onions; cook, stirring, until onions are translucent, 8 to 10 minutes. Transfer carrot mixture to quinoa. Stir in walnuts, oregano, cheese, salt, and pepper.
Heat oven to 400 degrees. Lightly spray a large ovenproof casserole with cooking spray. Fill each pepper with quinoa mixture; arrange in casserole. Heat peppers in oven until warm, and tops are slightly crusty, 20 to 30 minutes.
Warm ancho-chile sauce in small pan over medium heat. To serve, arrange a pepper on each plate, surround with sauce, and sprinkle with walnuts and oregano. Serve warm.
Medium-size fresh poblano peppers are the best ones for stuffing.