Char peppers on gas grill, over gas flame on range, or in preheated broiler, turning occasionally, until black on all sides. Allow to cool slightly, then core and halve peppers, remove ribs and remaining seeds, scrape off skin, and set aside.
In a small saucepan, sweat onion and garlic in olive oil over medium-low heat until onion is very soft, then drain.
Meanwhile, place potatoes in a saucepan with cold salted water to cover. Bring to a boil over high heat and continue boiling until potatoes are done (about 20 minutes). Drain, allow to cool slightly, and mash well in a large bowl. Add crème fraîche or crema mexicana and mix well, then fold in crabmeat, scallions, and lemon juice.
Bring cream to a simmer in a saucepan. Meanwhile, purée peppers with softened onion and garlic in a blender or food processor. Stir purée into hot cream and return to a simmer, then remove from the heat and season with salt, pepper, and paprika to taste.
In a medium skillet, heat ¼″ of olive oil over high heat until very hot but not smoking. Using tongs, dip tortillas one by one in oil and fry for a few seconds on each side. Drain tortillas and stack them between paper towels. Add more oil to skillet and reduce heat slightly if oil begins to smoke.
Meanwhile, cook the peas al dente in boiling salted water. Drain and set aside.
Remove foil from enchiladas, crumble blue cheese on top, and continue baking, uncovered, until cheese is just melted. Serve enchiladas scattered with peas.
© 1992 Colman Andrews. All rights reserved.