Additional butter and sugar to prepare the ramekins
PREPARE RAMEKINS: Brush the ramekins with softened unsalted butter. Brush from bottom upwards. This will make the soufflé to rise evenly. Then, coat the ramekins with sugar. And shake out any excess; set aside.
BECHAMEL SAUCE (white sauce: step 2-4): Over medium heat, add butter in the sauce pan and melt it. Add in the flour and cook for 1 minute stirring with a wooden spoon. This is white roux.
Remove the pan from the heat, gradually add hot milk, and stir until smooth and combined. Back to medium heat stir constantly until it comes to a boil. The sauce should form ribbons. This is white sauce. Remove from the heat.
Add in salt and vanilla extract and stir until combined. Separate the eggs and add in the egg yolks one by one and stir to combine. The sauce pan is still warm, so pour the sauce into a separate bowl to prevent unwanted evaporation; set aside.
MAKE FRENCH MERINGUE: Whisk egg whites. It is not mixing. It is incorporating the air. Keep whisking until firm peaks form. Add gradually sugar while slowly whisking. Keep whisking until soft peaks form. This is French meringue. It takes about 20 minutes with hand.
COMBINE: Add about one third of the French meringue into the white sauce and whisk until homogeneous. Then, pour all white sauce into meringue and whisk until just combined. Be careful not to crush the delicate meringue.
BAKE: Spoon the mixture into ramekins. Run thumb around inside of rim. This will help the soufflé to rise straight. Bake in the oven preheated to 390° F. (200° C.) for 12 to 15 minutes, or until well risen.
SERVE: Place on a plate because ramekins are very hot. Dust with confectioners’ sugar and serve immediately out of oven.