For the meringue, heat the oven to 180°C/fan160°C/gas 4. Draw an 18cm circle on each of 4 sheets of baking paper, then use to line 4 lightly oiled baking sheets.

Grind the nuts in a food processor with 1 tbsp of the caster sugar until finely ground with some texture – don’t overgrind or it will become oily.

Put the egg whites in a spotlessly clean mixing bowl and whisk with an electric hand mixer to stiff peaks.

Add the remaining caster sugar to the whites a tablespoon at a time, whisking back to stiff peaks each time.

Once you’ve added half the sugar, start adding in larger quantities, whisking back to stiff peaks each time.

Once all the sugar has been added, whisk in the vinegar to form stiff peaks, then fold through the hazelnuts.

Spoon or pipe the meringues in circles onto the baking paper to give 3 flat circles and the fourth circle swirled a bit thicker.

Bake for 40 minutes until the edges are crisp and set and the insides are still gooey.

Take out to cool for 20 minutes on the trays, then transfer carefully to wire racks or boards to cool fully.

For the PX sherry chocolate cream, put the chocolate, sherry and brown sugar in a large, heatproof bowl set over a pan of barely simmering water.

Melt, stirring very occasionally, until smooth, then remove from the heat, stir in 150ml of the cream and leave to cool.

Whip the rest of the cream to soft peaks, then gently fold through the chocolate mixture.

Spoon the chocolate cream into a piping bag and snip off the end.

Put one meringue on a serving platter and pipe a third of the cream on top. Repeat with the next layers, finishing with the thicker meringue.

To decorate, melt the 50g chocolate and butter together, then cool a little. Drizzle all over the top, then scatter over the nuts.