Cocoa-Spiced Steaks with Red Wine–Chocolate Sauce

Stir together cocoa powder, salt, sugar, paprika, allspice, and cayenne in a small bowl. Set aside.

Pat steaks dry with paper towels. Rub 1 tablespoon cocoa mixture all over steaks. Place steaks on a plate, and let stand, uncovered, at room temperature 15 minutes. Meanwhile, stir together butter and remaining cocoa mixture in a small bowl; divide evenly into 4 portions in 4 small bowls. Set aside.

Heat oil in a large skillet over high until oil ripples and is almost smoking. Add steaks; cook, undisturbed, until browned in spots, 1 minute to 1 minute and 30 seconds. Using tongs, flip steaks. Cook until browned in spots on other side, 1 minute to 1 minute and 30 seconds. Using tongs, lift each steak, and press outside edges of steak into skillet, rolling steak until edges are browned, 15 to 30 seconds. Return steaks to lie flat in skillet. Reduce heat to medium; cook steaks, flipping often, until steaks are a rich dark brown in most areas, 1 to 2 minutes.

Add 1 butter-cocoa portion to skillet; cook over medium, turning often to coat steaks in melted butter, until a thermometer inserted in thickest portion of steaks registers 125°F to 130°F for medium-rare or 135°F to 140°F for medium, 1 to 3 minutes. Transfer steaks to a plate; partially cover with an inverted bowl, domed lid, or aluminum foil, and let rest until ready to serve.

Discard all but 1 tablespoon drippings in skillet. Reduce heat under skillet to medium-low, and stir shallot into reserved drippings; cook, whisking constantly, until shallot starts to turn translucent and no longer smells raw, about 1 minute. Add flour, whisking to evenly coat shallot. Whisk in wine, and bring to a boil over medium. Boil, undisturbed, until thickened, 1 to 2 minutes. Whisk in broth and any accumulated juices from steak plate. Increase heat to high, and bring mixture to a vigorous simmer. Simmer, whisking occasionally, until sauce reduces by almost half and lightly coats the back of a metal spoon, about 6 minutes. Remove skillet from heat; whisk in 2 butter-cocoa portions. Taste sauce; if desired, add cilantro or parsley.

Arrange steaks on plate. Spoon sauce over steaks, and top evenly with remaining butter-cocoa portion.