Camarones a la Diabla | Mexican Shrimp in Spicy Chile Sauce

Remove the shells and dark vein along the backs of the shrimp. Rinse under cold water and pat dry with paper towels. Rub with half of the lemon juice and salt, then refrigerate. Drying is important: wet shrimp will steam instead of sear when they hit the pan.

Remove the stems from the guajillo and chile de árbol peppers and shake out the seeds. To reduce the heat, cut the chile de árbol peppers down to two or omit them entirely. Toast the peppers in a dry pan for 30–40 seconds, until fragrant; remove them as soon as they begin to darken.

Heat the butter and olive oil in a wide pan and pour in the strained sauce; cover the pan halfway because it will splatter. Cook over medium heat, stirring occasionally, until the color deepens to dark red and the oil rises to the surface. Add the sugar and remaining salt and taste; the sugar is not there to make the sauce sweet, but to round out the heat of the chiles.

Raise the heat to medium-high and arrange the shrimp in a single layer in the sauce. Cook for 2 minutes on one side, then turn and cook the other side for 2 minutes. They are ready when pink and curled into a C shape. If they have curled into a tight O, they are overcooked, so stay by the pan.

Remove the pan from the heat, squeeze the remaining lemon juice over the shrimp, and sprinkle with chopped parsley. The sauce should coat the shrimp without pooling on the plate. If it is too thin, remove the shrimp and reduce the sauce for 2 more minutes. Serve with rice or warm tortillas.