Char poblano under broiler or over open flame on stovetop. Cool in covered bowl then peel, seed and chop.
Preheat oven to 350°F.
Combine softened butter with garlic, onions, cilantro, oregano, 2 teaspoons lime zest and juice of 1/2 lime. Pulse to combine.
Pat turkey or chicken dry and arrange on a cooling rack set over a baking sheet to let the heat circulate around the meat as it roasts. Top skin with 4 tablespoons butter. Roast 45 minutes or to internal temp of 170°F, until the skin is crisp and brown. Cover with loose foil and rest 10 minutes before carving.