1Preheat the oven to Gas 2/150°C/130°C fan. Line a baking tray with baking paper and draw a 20cm circle in the centre. To make the meringue, put the egg whites into a large, grease-free mixing bowl. Using an electric hand whisk on a low speed, start to whisk the egg whites and when foamy (after about 2 minutes), switch the whisk to medium. Continue to whisk for 1 minute, then turn to high and whisk until stiff peaks form and the mixture is light and fluffy
2Still on a high speed, whisk in the cornflour and then the sugar, a dessertspoon at a time, until the mixture looks stiff and glossy. (Adding the sugar slowly prevents the meringue weeping when cooked.) Lightly fold in the sifted cocoa powder using a metal spoon to make a swirly pattern – it shouldn’t be mixed in too thoroughly
3Spoon the mixture onto the circle marked out on the baking paper then, using the back of the spoon, make a crater in the centre, so that the sides are higher than the middle. Put in the oven, immediately turn the heat down to Gas 1/140°C/120°C fan, and bake for 1 hour until the outside of the meringue is crisp and the centre is slightly soft. Turn off the heat and leave the meringue in the oven until cold
4To make the topping, put the cherries in a small saucepan with the vanilla, cinnamon, caster sugar and a splash of water. Cook over a low heat for 5 minutes until the cherries are tender and juicy. Leave to cool
5To assemble the pavlova, place the meringue on a serving stand or plate. Mix together the crème fraîche and yogurt and spoon on top of the meringue, followed by the cherries and a little of the sauce; serve any surplus cherries and sauce in a bowl by the side. Grate the chocolate over just before serving.