Rhubarb, lime and ginger custard tart

Method

1. Put the flour and butter in a food processor with a pinch of salt and pulse until the mixture looks like breadcrumbs. Whisk together the egg yolk and water, then add 1-1½ tbsp of the mixture to the flour and butter. Pulse again until the mixture comes together and forms a dough. (Alternatively, rub the flour, butter and a pinch of salt together with your fingertips to a breadcrumb consistency, then quickly stir in the egg yolk and water mixture with a dinner knife to form a dough.) Use your hands to bring the dough together gently.
2. Flatten the pastry into a disc and wrap in cling film. Chill for at least 20 minutes.
3. Sprinkle a little flour onto a work surface (see tips) and roll the pastry with a rolling pin to a rectangle (or circle, for a round tin) 3-4cm larger than the tin. Turn the pastry regularly to stop it sticking, dusting with more flour if needed.
4. Use the rolling pin to lift the pastry and drape it over the tin, then press the pastry into the edges of the tin, pinching up the sides a bit so the pastry sits just above the level of the tin. Line with foil and fill with ceramic baking beans or uncooked rice, then chill in the freezer for 10 minutes or in the fridge for at least 30 minutes. Heat the oven to 210°C/190°C fan/gas 6½.
5. Blind bake the lined, filled tart case for 20 minutes, then remove the baking beans and bake for a further 5 minutes until the base is golden and feels sandy to the touch. Leave to cool. Using a serrated sharp knife, trim off the excess pastry around the top of the tart case to give a neat edge.
6. While the pastry is cooling, turn the oven down to 150°C/130°C fan/gas 2. In a large jug whisk together the cream, whole eggs and yolks, vanilla, sugar, ginger syrup (not the chopped ginger) and lime juice.
7. Put the cooled pastry case on a lipped baking sheet and arrange the rhubarb and chopped stem ginger over the base. Pour in the cream mixture. Transfer to the oven and bake for 50 minutes (55-60 minutes if using a round tin) or until set but with a slight wobble in the middle. Leave to cool completely, then sprinkle over lime zest to decorate. Slice diagonally to serve.