Heat the oven to 180C/fan 160C/gas 4. Use a dinner plate to draw a circle on a sheet of baking paper, then flip over onto a solid baking sheet.
Whisk the egg whites with electric beaters until they just form stiff and shiny peaks. Gradually add the sugar a couple of tablespoons at a time and whisk really well between each addition. When all of the sugar is used up, continue whisking for 3-4 minutes or until the meringue is stiff and glossy and stands up in peaks, then whisk in the cornflour and vinegar.
Pile the mixture onto the baking paper and form into a circular shape, but with a few peaks around the edge. Put in the oven, turn the temperature down to 120C/fan 100C/gas 1/2 and cook for 11/2 hours. Turn the oven off and leave the meringue inside until completely cold.
Carefully peel off the baking paper and put the pavlova onto a serving dish. Don’t worry if it cracks a little as this is quite normal and the cream and chocolate will cover it.
Drizzle with the melted chocolates then put in the fridge for 10 minutes to set.
To make the chocolate curls for the filling, melt the dark chocolate then spread over a clean baking sheet in a very thin layer. Put in the fridge until just set, then use a large chef’s knife to draw through the chocolate towards you in a semi-circle. The chocolate should curl up into round shavings.
Put the vanilla, cream and Baileys Irish cream in a bowl. Whip to soft peaks.
Pile the cream into the pavlova and finish with dark chocolate curls.