1. Heat the oven to 450°. In a small bowl, combine 2 tablespoons of the butter with the oregano, cumin, 1/4 teaspoon of the salt, and 1/4 teaspoon pepper.
2. Rub the mixture over the skin of the hens and arrange them, skin-side up, on a baking sheet. Roast in the upper third of the oven until golden and cooked through, about 20 minutes.
3. Meanwhile, combine the remaining 2 tablespoons butter with the scallion, the remaining 1/4 teaspoon salt, and 1/8 teaspoon pepper. When the hens are roasted, top with the scallion butter. Serve with lime wedges.
Menu Suggestions: You could roast new potatoes right alongside the hens with almost no effort. Sautéed bell peppers would complete the meal.
Variation: Cornish Hens with Herb Butter and Lime: Mix one tablespoon chopped fresh herbs, such as chives, parsley, and/or oregano, with the butter in place of the scallions.
Wine Recommendation: A number of hearty red wines would be nice with the straightforward, rustic flavors here. Look for a Corbières from the south of France, a zinfandel from California, or a Rosso di Montalcino from Tuscany in Italy.