Nutrition: Per serving (6)
First, make the filling. Push the chestnut purée through a sieve using the back of a spoon into a bowl or the bowl of a stand mixer. Pour in the cream and vanilla, then sift in the icing sugar. Add the brandy or liqueur and beat using an electric whisk or in the stand mixer for a few minutes until the mixture creates soft peaks. Chill until needed.
Sift the flour and a pinch of salt into a bowl and set aside. Warm the butter and 225ml water in a saucepan over a low heat until the butter has melted and the mixture is simmering. Stir in the seasoned flour and beat using a wooden spoon until everything has come together into a smooth dough that pulls away from the side of the pan. Spread the mixture out over a plate to quickly cool until just warm. Heat the oven to 200C/180C fan/ gas 6 and line two baking sheets with baking parchment.
When the dough has cooled slightly, scrape it into a bowl and beat in the eggs one at a time using a wooden spoon or electric whisk. You may not need all the eggs to achieve the right consistency – the dough should be smooth, silky and slowly fall off the spoon in a ‘V’ shape. Spoon the dough into a piping bag and snip off the end so you have a 1cm opening, or simply use the spoon to scoop the pastry if you don’t have a piping bag.
Pipe or scoop walnut-sized balls of dough over the two baking sheets, being sure to leave a good amount of space between each. (You should have about 20 in total.) Bake for 30-35 mins, turning the trays around after 20 mins, until the profiteroles are puffed up and crisp. To ensure they don’t become soggy, you can poke a hole into each profiterole using a skewer and return them to the oven for a few minutes. Leave to cool completely.
For the sauce, warm the cream and syrup, if using, in a pan over a low heat or in a heatproof bowl in short bursts in the microwave until steaming. Add the butter and chocolate, stir a few times, then leave to melt for 10 mins. Stir the mixture until glossy, then set aside.
Cut each cooled profiterole in half, then pipe the filling into the bottom halves until it comes slightly over the edge. Sandwich with the tops, then arrange the filled profiteroles on a cake stand or platter, stacking them on top of one another. Pour over the sauce. If it has cooled and thickened too much, warm it over a low heat or in short blasts in the microwave until it’s pourable again. Sprinkle over the chopped marron glacé.
