Method

1. Heat oven to 220C/200C fan/gas 7. Line a large baking tray with baking parchment and grease lightly with oil. Sprinkle 1-2 tsp of water over the surface of the parchment with your fingers.

2. To make the choux buns, pour 100ml water into a small saucepan and add the butter. Heat until the butter has completely melted and the mixture starts to simmer. Take the pan off the heat and quickly add the flour and the caster sugar, stirring vigorously with a wooden spoon to remove any lumps. Working quickly, add the egg, bit by bit, beating continuously until you have a smooth, thick and glossy batter. Allow to cool for 5 mins, then transfer the mixture to a disposable piping bag and snip off the end.

3. Pipe 4 large buns onto your prepared tray (approximately 8cm in diameter) and 4 mini ones (approximately 4cm in diameter). Leave space between each bun, as they will spread as they cook. Bake for 18-20 mins or until well risen and golden brown. Take the tray out of the oven, transfer the smaller buns to a wire rack (as they will have cooked slightly quicker) and pop the larger buns back in the oven for a further 2-3 mins.

4. Split all the choux buns in half as soon as they come out of the oven, then lay them, cut-side up, on a baking tray and return to the oven for a further 2 mins. This will allow the steam to escape and crisp up the pastry inside. Leave to cool, cut-side up, on the tray or a wire rack.

5. While the pastry is cooling, make the filling. Whip the cream together with the icing sugar and vanilla until just starting to thicken (try not to overwhip the mixture as it will continue to thicken when it is piped). Fold in the crème fraîche. Spoon into a disposable piping bag and chill until needed.

6. To make the icing, mash the raspberries with a fork, then push the juice and pulp through a sieve using the back of a spoon. Discard the seeds. Stir the icing sugar into the sieved pulp to create a thick pink icing – if the mixture is too runny, add a little more icing sugar. Use to decorate the top halves of all of the choux buns, then leave to set.

7. For the buttercream, use an electric whisk to beat the butter, milk, vanilla extract and icing sugar together until pale and fluffy. Scoop into a piping bag fitted with a star nozzle.

8. To assemble, place the bases of all the choux buns on a serving platter and fill with the cream mixture and the remaining raspberries, reserving 4 for decoration. Top the choux buns with their pink lids, then pipe a small amount of buttercream at the centre of the top of the 4 large filled buns. Place a small choux bun on top of the buttercream and press gently so that it sticks. Use the rest of the buttercream to pipe short blobs starting on the large choux bun and ending halfway up the small bun. Finally, pipe a tiny amount of buttercream into the cavity of the 4 remaining raspberries and use this to fix it in place on the very top of each bun. Serve immediately.