Heat oven to fan 120°C. Line 2 large baking sheets with non-stick baking paper. In a large bowl, whisk the egg whites until stiff.
Gradually whisk in the sugar 1 tbsp at a time until the mixture is very stiff and shiny. Sift in the corn flour then, using a large metal spoon, fold in along with the vinegar. Divide the mixture into 8 mounds and place on the parchment paper. With a dessert spoon, flatten each one out to approximately 9cm in diameter and make a light indent in the centre of each.
Cook for 40-50 mins or until the meringue mixture is hard and the baking parchment peels away easily from the bottom of the each one. Cool on a wire rack.
Place the pears in a medium pan in a single layer - they should fit quite tightly. Add the honey, apple juice and cinnamon stick. Bring to the boil, then turn down the heat, cover with a round of baking parchment and a lid. Simmer for 35-40 mins until pears are tender. Remove lid and paper, turn up the heat and allow the liquid to bubble away until it has turned to a sticky glaze. Leave to cool.
Meanwhile, make the chocolate sauce and cream filling. Put the cream in a pan and heat gently until it just starts to boil. Tip in chocolate and stir until it has melted and the sauce is smooth. Whip the cream until soft peaks form and then mix together the cream and Greek yogurt until thick, but still soft.
To serve, put the meringues on serving plates and top with a dollop of the cream filling. Place a glazed pear on top and drizzle with some warm chocolate sauce. Serve straight away, handing round any extra sauce.