Steak Diablo

Two l-inch-thick steaks
1/2 cup minced onion
3 tablespoons unsalted butter

1/2 teaspoon dried hot red pepper flakes, or to taste
a pinch of cayenne, or to taste
a dash of Tabasco, or to taste
1 teaspoon Worcestershire sauce
1 teaspoon sugar
1/3 cup brandy
1/2 cup beef broth

Season the steaks with salt and pepper and broil them on the rack of a foil-lined broiler pan under a preheated broiler about 4 inches from the heat for 5 minutes on each side for medium-rare meat. While the steaks are broiling, in a skillet cook the onion in the butter over moderately low heat, stirring, until it is softened and stir in the red pepper flakes, the cayenne, the Tabasco, the Worcestershire sauce, and the sugar. Add the brandy and boil the mixture until it is reduced by half. Add the broth and boil the sauce until it is reduced by half. Season the sauce with salt and pepper and serve it with the steaks.