Bring the water to a boil in a fairly large pan and add the salt.
Add the butter and let it melt.
Mix the flour and cornstarch and tip into the water all at once, stirring constantly until the mixture forms a smooth ball.
A thin white layer will form on the base of the pan.
Beat the pastry mixture over the heat for a further 2 minutes.
Then transfer to a mixing bowl and gradually beat in the eggs, one at a time, only adding the next egg when the previous one is completely mixed in.
Grease a cookie sheet and lightly dust with flour.
Spoon the pastry mixture into a piping bag with a large plain nozzle and pipe 4-6 balls onto the sheet.
Bake in a hot oven (180°C) for 20-25 min.
Take out of the oven and split the profiteroles immediately to release the steam (but don't take them apart).
Drain the peaches. Fill the cooled profiteroles with peach slices sprinkled with sugar and sweetened whipped cream.
Put the lids on, dust with confectioners' sugar and serve.