Step 1

Sift the flour onto a sheet of baking paper. Put the sugar, butter and ½ tsp fine salt into a large pan with 240ml of water. Heat very gently until the butter has melted, then increase the heat and bring the liquid to the boil. As soon as it’s bubbling, lower the heat, tip in the flour (use the baking paper as a chute) and beat it in with a wooden spoon until the mixture forms a smooth dough that clumps together, leaving the rest of the pan clean. Carry on beating and cooking over a low heat for 5 minutes – steam should continue to rise from the mixture.

Step 2

Cool for 5 minutes, then add in the egg a little at a time, beating in completely between each addition, until the dough is smooth and glossy but still thick – you may not need to use all of the egg. It should drop very reluctantly from the spoon in the shape of a ‘V’ when you bang it against the side of the pan – too runny and you won’t be able to pipe it, too thick and the buns won’t puff up in the oven. Dampen a sheet of baking paper and use it to line a big baking sheet (or two small ones).

Step 3

Heat the oven to 200C/fan 180C/gas 6.Transfer the dough to a piping bag fitted with a large round nozzle, and pipe 30 walnut-sized balls, spaced apart for rising. Dip your finger in a little water to smooth out any bumps or peaks in the dough, then put the tray or trays in the oven and bake for 30-35 minutes until the profiteroles are puffed, golden and crisp. Turn off the oven and leave the profiteroles in for another 30 minutes, then transfer to a wire rack to finish cooling.

Step 4

Make the chocolate sauce by putting the sugar, cocoa and golden syrup in a pan with 200ml water. Whisk together over a medium heat then, once it begins to boil, bubble fiercely for a minute, remove from the heat and stir in the chocolate until it has melted. Pour into a bowl and leave to cool, then cover and chill.

Step 5

For the hazelnut brittle, line another baking sheet with baking paper and sprinkle over the chopped hazelnuts. Heat the sugar in a medium pan without stirring. When it’s melted, bubble until it turns a golden caramel colour. Pour straight onto the baking sheet, tilting to spread as thinly as possible and cover all the nuts. Once set, bash the brittle in a food processor into small pieces, and whizz 1/3  of these to make a sugar ‘dust’.

Step 6

For the filling, put the Nutella into a bowl with 1/2 the Frangelico and 1/2 the icing sugar, and gently whisk until combined. Pour in 1/2 the cream and whip to soft peaks with electric beaters. Pour the remaining cream into a separate bowl with the remaining icing sugar and Frangelico, and whip this to soft peaks as well.

Step 7

When the profiteroles are cold, you’re ready to assemble. Poke holes in the bottom of each bun with a small piping nozzle. Spoon both fillings into separate piping bags fitted with small nozzles, and pipe into 15 profiteroles each, until they feel heavy and the cream wants to squirt back out.

Step 8

To assemble, dunk each profiterole in the chocolate sauce to cover the top as you stack on a serving plate. Sprinkle over the nutty brittle shards and dust, and serve the profiterole tower.