Preheat oven to 375°F degrees. Grease three (5 or 6-ounce) or two (8.5-ounce) ramekins lightly with butter. Sprinkle the inside with granulated sugar. Invert and tap ramekins to remove excess sugar; discard. Set ramekins aside.
In large heatproof bowl set over saucepan of hot (not boiling) water, combine 1 tablespoon butter, chopped chocolate, salt and 1 1/2 teaspoons water. Stir until the chocolate is melted. Remove from the heat and add the vanilla, cocoa powder and Bailey’s Irish Cream. Stir until smooth and well blended. Set aside.
In a separate bowl, beat egg yolks with 2 tablespoons granulated sugar until thick enough to form long ribbons that hold their shape for 2 seconds when beaters are lifted, about 2 minutes. Fold into chocolate mixture.
In separate bowl, beat egg whites (with clean, dry beater attachment) until foamy. Beat in cream of tartar. Add the remaining 1 tablespoon of sugar, a little at a time and then beat until stiff glossy peaks form; stir one-fourth of the egg-white mixture into the chocolate mixture. Fold in remaining egg whites until no streaks remain. Divide the batter between the prepared ramekins, smoothing tops. Run the tip of your thumb around inside edge of ramekins to wipe clean.
Bake on rimmed baking sheet at 375°F until tops are dry and centers are still jiggly, about 12 minutes for the smaller ramekins, and 15-18 minutes for the 8.5-ounce ramekins. Dust tops with powdered sugar or unsweetened cocoa. Serve immediately with the Bailey’s crème anglaise.