For the crust, place all ingredients except water into the bowl of your food processor then pulse until it resembles breadcrumbs with varying sizes of butter pieces, the largest the size of peas.
Add 3 Tbsp ice water and pulse until it mostly forms a ball. To test if it needs more water, take a piece and squeeze between your fingers. If it holds together, it’s ready. If it crumbles, add the last 1 Tbsp water and pulse again.
Tip out onto a lightly floured surface and gently bring together. Form a large disc then wrap in clingfilm and refrigerate for at least 30 minutes.
While dough is chilling, start on the raspberry curd. Blitz 250g of the raspberries in the food processor to purée then pass through a sieve set over a bowl to remove the seeds. Pour sieved purée into a measuring jug. You need about 250ml in total, so if you don’t have enough, purée and sieve more raspberries until you have enough.
Mix a few tablespoons of raspberry juice with cornflour so that you have a smooth mixture with no lumps. Combine this with the rest of the raspberry juice in a medium sized pot, then add the sugar, egg yolks and whole eggs.
Over medium heat, cook together, stirring constantly, until the curd thickens to a pudding consistency (it should drop off the spoon rather than pour off in a stream.)
Remove from heat and add the butter. Stir until completely melted then add a few drops of pink food colouring and stir through until you get the shade of pink you prefer.
Cover the curd with a piece of clingfilm, pressing it against the surface, and leave to cool until room temperature.
Continue with the pastry. Remove chilled pastry from the fridge then gently roll it out with a rolling pin so that it is large enough to fill your tart tin (this is enough for a 23cm / 9inch round tin or 10x35cm / 4x14inch rectangle tin). Make sure to keep the pastry moving so that it doesn’t stick.
Dust off excess flour then carefully lift it and lay it in the tin. Use the palms of your hands and pads of your fingers to gently press the pastry into the tin and up the sides. Use a fork to prick the surface of the pastry then chill in the fridge, or better yet, freezer, for 15-20 minutes.
While pastry is chilling, preheat oven to 180°C / 160°C fan / gas 4 and place a large baking tray inside to heat.
Remove pastry from fridge or freezer and use scissors to trim away most of the excess pastry, but leave a slight lip above the sides, this will be trimmed later.
Line the pastry with a well crumpled piece of parchment paper and fill with baking beads or dried beans/rice.
Place in preheated oven on the heated baking tray and bake blind for 15 minutes.
Remove from oven and trim pastry to the top of the tin with a sharp knife. Use smooth singular motions and not sawing ones. Once excess has been trimmed, remove parchment with baking beads.
Return to the oven and bake until pastry is lightly golden, 20-25 minutes.
Remove from oven and leave to cool completely in the tin on a wire rack.
Once both curd and pastry are completely cool, pour raspberry curd into the pastry (you may have a little left over if using the rectangle tin. Keep the leftover to enjoy on pancakes, scones, toast or in yoghurt.) Smooth the top with a spatula then gently tap against the counter top to bring up any bubbles and further smooth the surface.
Keep chilled in the fridge until ready to top with meringue and serve.
To serve, make the meringue. Place egg white into a medium sized bowl and beat with electric mixer until it starts to become frothy.
Still whisking, slowly add the sugar, 1 tsp at a time. Increase speed of mixer as you whisk.
Once all the sugar has been dissolved and the meringue is glossy with stiff peaks, whisk in vanilla seeds.
Spoon meringue into 1-3 piping bags (depending on how many piping tips you would like to use) then pipe meringue kisses on top of the raspberry curd.
Sprinkle with raspberry powder, if using, and decorate with a few fresh raspberries.
Best served shortly after decorating. If you wish to make ahead, either keep the curd-filled pastry in the fridge undecorated for up to 3 days in an airtight container, or, decorate using sweetened whipped cream instead of meringue.