Stir the sugar, salt, and water together in a small bowl until the sugar and salt are fully dissolved. Place the bowl in the freezer so the liquid can chill down and be ice cold when making the dough.

Mix the flours together in a large mixing bowl and add the pieces of butter. Use your clean hands to squeeze the butter into the flour until you have pea size pieces of butter.

Drizzle the sugar water mixture of the flour and mix, again with your clean hands, until a shaggy dough has formed and all the flour is moistened by the water. It will be crumbly at first but will come together the more you mix it. Keep mixing until a shaggy ball has been formed. Flatten the mound into a 1 inch thick disk and wrap in plastic wrap. Stick in the fridge to chill for at least 2 hours or overnight.

Once chilled, transfer your disk onto a floured surface and roll the dough out into a 12 inch circle. Transfer to a 9 inch pie pan, letting the extra dough hang off the sides. Roll the extra dough hanging off the edge underneath itself until it lays on the rim of the dish. To make a crimped edge, place a piece of the edge between your thumbs and a index finger to create a crimp look and repeat this process all the way around. Alternatively, you can use a fork to make fringe decoration around the crust. Transfer to the freezer to let chill while the oven preheats.

Preheat oven to 375 degrees. Once the oven is ready, remove pie crust from the freezer and top with parchment paper followed by pie weights (I always used dried beans). Blind bake for 20 minutes, carefully remove the parchment paper and pie weights, and bake for another 10 to 15 minutes or until the bottom of the crust looks fully baked (shouldn't be wet looking at all). Transfer to a wire rack and let cool completely.

In a medium bowl, whisk together 1 1/4 cup sugar, cornstarch, and 1/4 tsp salt. Whisk in the egg yolks, whole egg, and 1/4 cup plus 2 Tbsp water. Whisk in the lemon juice then pass the mixture through a fine mesh strainer into a small saucepan.

Place the pan over medium high heat and stir constantly with a rubber spatula, scraping the sides to prevent burning, for 5 to 8 minutes or until the mixture starts to thicken. Reduce the heat to the lowest setting, continue to stir constantly, and cook until the consistency is thick but still pourable, about 5 more minutes. Remove from heat and stir in 3 Tbsp cold butter until melted.

Pour the hot filling into your blind-baked pie crust and use the spatula to ease the filling into an even layer.

Using a clean and dry bowl fitted on a stand mixer with the whisk attachment, beat the egg whites and cream of tartar on high until they are white, foamy, and hold soft peaks.

Meanwhile, in a small saucepan, stir 1/4 cup water and 1 cup sugar over high heat until the sugar has dissolved and the syrup reaches a strong boil (a candy thermometer should reach 240 degrees). Remove from heat.

With the stand mixer running, slowly pour the hot sugar mixture in a thin stream into the foamy egg whites. Continue beating until the meringue holds the pattern of the whisk and the texture is voluminous and silky. Add the vanilla, salt, and poppyseeds, and beat just until combined.

Pile the meringue on top of the lemon curd and use the back of a hot, wet spoon to create a wavy texture with peaks and valleys.

Set an oven rack in the middle and place the pie on it so that the pie is 3 to 5 inches from the top. Turn the broiler on high and broil just until the golden brown, about 1 to 3 minute. Watch closely as broilers vary widely and could take less or more time.

Transfer the pie to the fridge and chill for at least 4 hours. The pie will keep for up to 4 days, covered in the fridge.