1. To make a lemon meringue tart, preheat your oven to 200°C. On a floured surface, roll out some pastry and use it to line a 20cm tart tin with a removable bottom. Prick the base with a fork, then chill it for 20 minutes. Place the tin on a baking sheet, line the pastry with non-stick baking paper. Bake for 15 minutes, remove the paper then bake for another 15 minutes or until the pastry is golden. Let it cool, then trim the edges with a serrated knife.

2. Meanwhile, make the lemon filling by whisking together some cornflour, sugar, lemon zest, and lemon juice in a saucepan. Gradually add some milk and cook the mixture over low heat, whisking constantly, until it thickens and boils. Take it off the heat and whisk in some butter, egg yolks, and a whole egg. Set aside.

3. For the meringue, beat some egg whites until stiff peaks form, then add sugar gradually, whisking until thick and shiny. Mix in some cornflour.

4. Bring the lemon filling back to a boil, stirring until it thickens, then pour it into the pastry case. Spoon the meringue on top, starting at the edge and working inward. Use a palette knife to smooth the top and join it to the pastry edge. Swirl the meringue.

5. Bake the tart for 20 minutes or until the meringue is golden. Let it cool in the tin for at least 1 hour before removing and serving it warm or cold.