Gin & Tonic Tart

First, make the pastry case; sift the flour and icing sugar, then put them into a food processor. Add the butter and lemon zest and process until the mixture looks like fine crumbs. Gently pour in the tonic water, tip in the egg yolk and mix again until the pastry dough forms a smooth ball. Wrap the dough in clingfilm and put in the fridge to chill for about 30 minutes.
When the 30 minutes is nearly up, lightly grease a 23cm loose-bottomed tart tin. Turn the chilled pastry dough out on to a lightly floured surface and roll it out to about 5mm thick. Lift the pastry carefully on to the tart tin and press it down gently to line the tin, trimming the edges to neaten if needed. Put the tin back in the fridge to chill for another 15 minutes.
Preheat the oven to 180°C. Take the pastry case out of the fridge, and use a fork to prick the base a few times. Line the case with baking paper and fill it with baking beans (or uncooked rice), then put it into the hot oven and cook for about 10 minutes. Remove the case from the oven, take out the baking beans and paper and return the case to the oven for five more minutes, or until just golden. Allow to cool.

To make the filling, whisk together the eggs, caster sugar, lemon zest and juice, cream and gin. Pour the mixture into the cooled tart shell and bake for about 20 minutes, or until just set.
While the tart is cooking, make the gin & tonic syrup; put the sugar, tonic water and lemon juice into a saucepan over a low heat. Stir until all the sugar is dissolved, then add the gin to the pan, increase the heat and simmer for 5-10 minutes, until the syrup has thickened slightly. Add the lemon zest strips to the syrup and simmer for a further five minutes, then take the pan off the heat and allow to cool completely.

When the tart has cooked, drizzle the syrup over it and serve straight away.