Photograph: Dan Jones
Preheat the oven to 220°C, fan 200°C, gas 7. Sift the flour and a pinch of salt on to a square of greaseproof paper that you have folded in half and opened again (this will make it easier to add the flour to the liquid quickly).
Over a low heat and in a medium pan, gently heat 300ml of water, the sugar and the butter. Once the butter has melted, turn the heat up and, as soon as the liquid comes to the boil, shoot all the flour from the greaseproof paper into the pan and take the pan off the heat (this is important to prevent too much liquid evaporating). Using a wooden spoon, quickly mix the flour into the liquid. You will need to beat vigorously and keep going until the mixture comes away from the sides of the pan.
Little by little, beat in the eggs, making sure the egg is fully absorbed into the dough with each addition. You will be left with a thick, glossy paste. Leave to cool a little.
Using half the choux pastry, place 20 heaped teaspoonfuls of the mixture on the lined baking sheet. Roll into balls. Make sure you leave enough space between each ball for the pastry to rise and expand. Bake the choux buns for 20 minutes (it's best to bake one tray of profiteroles at a time). Remove from the oven and reduce the temperature to 200°C, fan 180°C, gas 6. Quickly turn the profiteroles over and prick each one with a wooden cocktail stick to allow the steam to escape. Return to the oven, bottoms up, and bake for a further 5-7 minutes, or until golden and crisp. Transfer to a wire rack to cool. Bake the second half of the choux pastry in the same way – remember to increase the oven temperature to 220°C, fan 200°C, gas 7 before you start again.
Using a sharp knife, halve the cold choux buns. Mix the crème fraîche with the vanilla seeds and, using a small teaspoon, fill the bottom half of each bun. Put the lids back on. Melt the chocolate in a bowl over a pan of barely simmering water and, using a flat-bladed knife, spread a little melted chocolate on top of each profiterole. Leave to set for an hour or so.
Top the profiteroles with crushed crystallised rose petal pieces and pieces of gold leaf. Pile on to a serving plate or into bowls.
Get ahead: best made and eaten on the same day. Once filled and decorated, the profiteroles are best kept in a cool place (not the fridge) for a few hours before serving.
Kitchen secret: making choux pastry really is a doddle – there’s no chilling or rolling out and no fear of holes in the pastry. Once the buns are made they just need to be filled and topped.