Preheat broiler and roast peppers in a large roasting pan, turning several times, until skins are charred all over. Transfer peppers to a large bowl and seal tightly with plastic wrap. Let steam 20 minutes, until skins loosen. When cool enough to handle, remove skins and seeds from peppers, and coarsely chop.

In a large sauce pan, over medium heat, add the oil, when hot add the  carrots, onion and garlic and cook until the vegetables are tender, 5 minutes. Add roasted peppers, tomatillos and ground Ancho chile powder; cook 1 minute. Stir in stock, potatoes and spices. Bring to a boil, lower heat to simmering and cook until potatoes are tender, about 30 minutes. Season to taste with salt and pepper. To serve, ladle stew into 4 bowls and garnish with a few cilantro leaves and queso fresco.