Preheat oven to 120°C. Put egg whites and a pinch of salt in a grease-free bowl and mix with an electric mixer until very stiff.

Continue beating while adding caster sugar a tablespoon at a time. Whisk for several minutes until very stiff then turn off machine and sprinkle over cornflour, vinegar and vanilla extract. Use a large metal spoon to carefully mix ingredients together without deflating the whipped whites.

Transfer mixture in dollops to a baking tray lined with baking paper and shape into a rough round, about 20cm in diameter – don't try to make it perfect and smooth because you'll knock out air.

Bake in oven for 1 hour, by which time the meringue should be crisp on the top; it may be slightly sunken under the crisp shell but this is normal. Turn oven off and leave pavlova in oven for at least 1 hour but preferably until the oven is cool (overnight is fine, just remember to remove it before you start the oven again).

Just before serving, carefully peel away baking paper from underneath pavlova and transfer pavlova to a cake plate.

Beat yoghurt until smooth then put dollops of yoghurt on top of the pavlova. Strew with raspberries then either leave at room temperature for up to 2 hours, or transfer to the fridge.

Dust raspberries with icing sugar before serving. I think the pavlova is at its best about 4-8 hours after assembling.