How to Make It
In a large bowl, mix the paprika with the ancho chile powder, brown sugar, cumin, salt, pepper and garlic. Add the shrimp and toss to coat in the spices.
Heat 1/4 cup of the oil in 2 large skillets until shimmering. Add the shrimp to the skillets and cook over moderately high heat, stirring occasionally, until curled and white throughout, about 4 minutes. Add half of the butter and scallions to each skillet and swirl them in. Transfer the shrimp to a platter and serve.
If you don't want to fuss with shells, you can use shelled shrimp. Cut the cumin in half and cook over moderate heat.