Use a pre-made dough (e.g., Tarte Tatin dough) or roll out your own. Bake the tart shell alone in a preheated oven at 180ºC (350°F) for about 25 minutes. Set aside to cool.

In a saucepan, whisk 3 egg yolks with 150g sugar. Add 50ml water and 30g cornflour dissolved in another 50ml water.

Add 150ml water, the zest of 3 lemons, and the juice of 3 lemons. Cook over low heat until thickened. Remove from heat and stir in 30g butter or margarine.

Pour the lemon cream into the pre-baked tart shell and smooth the surface.

Whisk 3 egg whites with a pinch of salt until stiff, then gradually add 100g sugar. Spread the meringue over the lemon cream. Bake for 5 seconds at 250ºC to brown lightly. Chill for 30 minutes in the fridge before serving.