Boil the skimmed milk in a saucepan. when its just boiled, take it off the heat.

Stir in the coffee and set aside.

Prepare the ramekins by brushing them with the butter and dusting with castor sugar.

To prepare the 'roux' - in a heavy bottomed saucepan, place the flour, castor sugar and butter. mix to combine.

Using a balloon whisk, pour in the warm coffee-milk and whisk continuously over medium heat, ensuring that no lumps form. bring to the boil, and simmer for about a minute (all the while whisking).

Add the yolks one at a time, and whisk till well incorporated. the roux is ready; set aside to cool slightly.

Whisk the egg whites well until stiff peaks form (the more you whisk, the lighter your souffle turns out).

Fold in the whisked egg whites bit by bit into the roux (be sure to FOLD, not MIX).

When all the egg whites are incorporated into the roux, divide the mixture between the four prepared ramekins.

Arrange the ramekins in a preheated oven, heated to 180 degrees C. make sure to place the rack on the lowest position, to account for the rising souffle.

Bake for 25 - 30 minutes, till the souffle is well risen. (you can tell its done when you see a big 'crack' in the top surface of the risen souffle)

Remove from the oven and serve immediately with either whipped cream or ice-cream. the souffles tend to collapse if left for too long after baking, so make sure you serve them straight out of the oven.