To make choux pastry, add the butter and salt to 225ml water in a pan and bring to the boil. Tip in the flour and whisk until the mixture clings to the whisk. Then, using a wooden spoon, beat well on the heat for 2-3 minutes until the mixture is glossy.

Transfer the mixture to a food mixer and beat for 1 minute. Add the eggs one at a time while keeping the mixer running. Go carefully with the eggs as you may not need them all. You are aiming for a smooth and glossy mixture that will hold its shape

Preheat the oven to 170 °C/gas mark 3. Lightly grease a non-stick baking tray. Fit a plain nozzle about 1cm diameter to your piping bag and fill with the choux pastry. Pipe 12 lines of choux, 12-15cm long, onto the baking tray.

Bake the éclairs for 15-20 minutes until golden and puffed up. For the last 4 minutes, leave the oven door slightly ajar to allow the steam to escape and help the drying process. Remove them from the oven and leave to cool.

Once cooled, halve the éclairs lengthways, and separate the tops and bottoms. Put the chocolate into a bowl over a pan of simmering water, above water level. Turn the heat low to melt the chocolate slowly, stirring all the time. Dip the upper halves of the éclairs in chocolate, drain over the bowl, then leave to set on a tray.

Whip the cream into soft peaks. Sprinkle the sugar over it and gently fold in. Fill your piping bag with the cream and pipe it on the choux bases in waves, then layer the banana slices on top, slightly overlapping them. Add dots of cream, then top with the chocolate-covered halves. Serve as soon as possible.