Preheat the oven to 170°C / 150°C (fan oven) / 340°F / Gas Mark 4. Line the base of a large baking tray with baking paper.

To make the meringue, whisk the egg whites using a stand mixer until they form stiff peaks. Continue whisking as you add the sugar, a spoonful at a time. Once the meringue is glossy, smooth and firm, fold through the zest and cornflour. Spoon the meringue onto the prepared tray and spread out to the edges. Bake for 1 hour then turn off the oven, leaving the meringue inside until completely cooled.

To make the curd, put the cornflour, lemon zest, juice, sugar and 4 tbsp water in a pan. Heat over a gentle heat, stirring continuously, until it boils and starts to thicken. Remove from the heat and whisk in the spread and egg yolk. Leave to cool.

To make the candied lemon, combine the agave syrup and 250ml water in a separate pan and bring to a boil. Simmer for 5 minutes, add the lemon slices and simmer for a further 5 minutes. Carefully transfer the lemon slices to a cooling rack and leave to cool completely.

Transfer the meringue to a serving plate, top with the lemon curd and yogurt and decorate with the candied lemon.