Whisk together flour, salt, and sugar in a large bowl. Slice cold butter into thin pieces and toss through the flour to coat. Cut the butter into small strips and rub into the flour with your fingertips until you have visible flat flakes throughout, but don't overwork it.

Make a well in the centre, pour in ice water, and mix until you have a shaggy, rough dough, it doesn't need to be smooth.

Shape the dough into a rough rectangle on a lightly floured surface. Fold it in thirds like a letter, rotate 90°, and roll out again. Repeat this fold-and-roll 2–3 times to build flaky layers.

Form the dough into a flat disc, wrap tightly in plastic wrap, and refrigerate for at least 2 hours.

Cut the dough in half (to get 2 shells in total) and roll out one half to about 3mm thick. Gently drape it into your pie tin, pressing into the edges. Trim any excess and chill for 4 hours or overnight.

Preheat your oven to 200°C. Dock the chilled pastry all over with a fork, line with baking paper, and fill with pie weights or dried beans. Bake for 15 minutes.

Reduce the oven to 175°C and bake for another 15 minutes with the weights still in.

Remove the paper and weights, then return the crust to the oven and bake for a final 15 minutes until evenly golden. Set aside to cool completely.

Sprinkle gelatin over 125ml of warm water and stir. Let it sit for 5–10 minutes until fully hydrated.

In a saucepan, combine the remaining 875ml water with sugar and citric acid. Bring to a gentle simmer, stirring to dissolve the sugar. Add the bloomed gelatin and stir until completely melted. Remove from heat.

Let the jelly cool to room temperature. Don't rush this or you'll soften the crust. Pour the cooled liquid into the baked pie shell and transfer to the fridge to set until firm, at least 4 hours or overnight.

Place your stand mixer bowl in the freezer to chill. Set up a water bath with gently simmering water.

In a metal bowl, combine egg whites, sugar, kosher salt, and cream of tartar. Place the bowl over the simmering water and stir constantly with a whisk until the mixture reaches 79°C - this should take 7–10 minutes. All the sugar should be fully dissolved.

Transfer the hot mixture into your chilled stand mixer bowl. Whip on medium-high speed for about 10 minutes until you have stiff, glossy peaks. Transfer to a piping bag.

Pipe the Swiss meringue generously over the set jelly filling. Use a kitchen blowtorch to caramelise the peaks until golden brown. Serve immediately or keep chilled until ready.