Beat together the butter and the icing sugar until light in colour. Add the egg yolks, flour and water and bring together into a rough dough. Tip it out onto a floured surface and lightly work into a smooth dough then return to the bowl and cover with Cling Film. Rest in the fridge for 30 minutes.
Roll the pastry out into a circle on a floured surface to a thickness of about 2mm. Gently roll the pastry over the rolling pin and lower it over a fluted tart tin (28cm diameter). Press it into the tin, making sure there are no gaps between the tin and the pastry. Trim the edges so that they rise just above the top of the tin and return to the fridge to rest for another 30 minutes.
Preheat the oven to 180°C. Fill the tart tin with baking paper and tip over baking beans (or dry rice or lentils). Spread them over the surface of the tart case and blind bake for 10 minutes, until light golden brown).
In a large mixing bowl whisk the sugar and eggs together until pale. Zest in the lemons then squeeze in the juice (making sure to catch any pips). Whisk in the double cream to make a smooth mixture. Remove the baking beans and baking paper from the tart case and pour in the filling while the case is still warm.
Lower the temperature of the oven to 120°C and carefully return the tart. Bake for 30-40 minutes, until the filling has just a little wobble in the centre. Leave to cool to room temperature then place in the fridge for at least an hour to cool.
For the raspberry purée, place the raspberries and the water in a small saucepan. Bring to a boil and immediately remove from the heat. Blend in a food processor then strain through a sieve.
Dip the gelatine for the jelly into a bowl of cold water and leave it for 2 minutes to bloom. Pour the sugar syrup into a small saucepan, bring to a simmer over a medium heat then remove from the heat. Squeeze excess water out of the gelatine and add the sheet to the sugar syrup. Stir until it dissolves then pour in 125g of the raspberry purée and the white wine. Leave to cool to room temperature then pour it over the top of the cooled lemon tart. Return the tart to the fridge for a few hours, until the jelly is set.
Preheat the oven to 170°C. Place the star anise and the sugar for the crumb into a spice grinder and blitz, then sieve into a food processor. Add the flour, cornflour and butter to the food processor and blitz to a crumb. Tip the crumb onto a baking tray and bake for 15 minutes. Set aside to cool until needed.
Pour the egg whites into a stand mixer bowl fitted with the whisk attachment. Tip the sugar into a small saucepan and put it over a medium heat. Heat the sugar to 118°C. When the sugar reaches 110°C start whisking the egg whites to soft peaks. Very slowly pour the hot sugar into the egg whites when it reaches 118°C, while continuing to whisk. Continue to whisk until the bowl is no longer hot to touch. Pour in the 50g of raspberry purée and mix just enough to incorporate it. Pipe the meringue on top of raspberry jelly then blow torch for a golden colour. Finish with chopped mint and the anise crumb.