Add ice cubes and water to a measuring cup. Cut the butter into ¼" cubes. Place both items in the refrigerator until ready to use.

In a stand mixer bowl, add the flour and salt. Mix using the paddle attachment on the lowest speed for about 10 seconds. Add the chilled butter and mix until coarse crumbles form.

Gradually add 1 tablespoon of ice-cold water to the bowl until the dough looks lumpy and hydrated but not wet.

Press the dough into a 1” thick round disc, wrap in plastic, and chill for at least 4 hours.

Roll the dough into a 14-inch circle, slightly less than ¼" thick. Place it into a 9-inch pie dish and trim the excess.

Preheat the oven to 375°F (190°C) and freeze the crust for 20 minutes.

Bake the crust with parchment paper and weights for 20 minutes. Then, remove the weights and bake for another 15 minutes until golden brown.

In a bowl, whisk together ½ cup sugar and cornstarch. Add water and egg yolks. Set aside.

In a saucepan, combine water, sugar, lemon zest, lemon juice, and salt. Simmer until it reaches 190 to 200ºF.

Temper the egg mixture by gradually adding hot lemon mixture while whisking. Combine with the remaining lemon mixture and thicken.

Strain the lemon filling into the cooled pie crust. Cover with plastic wrap and chill until set.

In a stand mixer, beat the egg whites, vanilla, and salt until foamy.

Heat sugar and water in a saucepan to 240°F. Gradually add to the egg whites while mixing until thick and shiny.

Spread the meringue over the pie and toast with a kitchen torch.