Photo: Laura Edwards
Put the sliced lemon in a pan of boiling water and simmer for 10 minutes. Drain and set aside.
Put 100ml cold water and the caster sugar into a small frying pan. Heat gently, stirring to dissolve the sugar.
Add the lemon slices to the pan and bubble for 10-15 minutes or until the syrup has almost evaporated and the lemons are sticky and caramelised.
Using tongs, transfer the lemon slices to a tray lined with baking paper. Leave them to dry for a few hours.
Preheat the oven to 180°C / fan 160°C / gas 4. Butter a shallow baking dish, about 1 litre capacity. Whisk the butter, sugar and lemon zest together.
Whisk in the egg yolks, then add the milk and lemon juice gradually, whisking constantly. Next, whisk in the flour. The mixture will look a bit curdled, but that’s fine. In a separate bowl using clean whisks, whisk the egg whites to stiff peaks, then fold them into the mix.
Spoon into the dish and bake in the middle of the oven for 30-40 minutes or until the sponge is firm and golden.
Decorate with the candied lemon slices to serve.