1. Make the pie crust:

In the bowl of a food processor, place all of the pie crust ingredients except the ice water. Pulse until well combined. Add the ice water and blend again. Form the dough into a flat disk and wrap in parchment paper or wax paper. Refrigerate for 2 hours. Preheat the oven to 375 degrees F. Unwrap the dough and place it on a piece of parchment paper that has been dusted with a little flour. Sprinkle a little flour on top of the dough. Place another piece of parchment paper on top of the dough. Roll into a large thin circle. Carefully peel off the top layer of parchment and use the bottom piece to flip the dough into an oiled pie plate. Peel off the other piece of parchment paper. Crimp the edges. Add a fresh piece of parchment paper on top of the dough and cover with pie weights or dried beans. Bake for 15 minutes. Remove the parchment and pie weights or beans. Bake for another 7 minutes. Remove from the oven. Reduce the oven the oven temperature to 350 degrees F.

2. Make the pie filling:

In a small bowl, whisk the the egg yolks together. Set aside. In a medium saucepan, combine the water, raw sugar, arrowroot, sea salt, lemon juice, and lemon zest. Bring to nearly boiling over medium heat, while whisking. Reduce the heat to low and cook for 5 to 6 minutes, whisking occasionally, until it thickens. Very slowly stream in the egg yolks while whisking. Increase the heat to medium heat again, until bubbles break on the surface. Remove from the heat. Whisk in the butter. Pour into the pre-baked pie crust.

3. Make the meringue:

Place the egg whites in a large bowl or the bowl of a stand mixer. Add the cream of tartar. Using either a handheld mixer or a stand mixer fitted with a whisk attachment, beat the egg whites and cream of tartar together on medium speed for 1 minute. Increase the mixer speed to high and beat for 4 more minutes. Add the sugar and salt. Beat on high speed for a couple more minutes until stiff peaks form. Spread the meringue over the filling, covering the edges. Bake on the lowest oven rack for 23 minutes. You can carefully tent a piece of foil over the meringue to avoid over-browning. Once the pie has finished baking, remove from the oven and cool on a cooking rack for 1 hour. Refrigerate the pie for 4 hours before slicing and serving. Store leftover pie in the refrigerator for up to 24 hours.