To make pie crust, combine flour and salt in a food processor. Pulse a few times to combine. Scatter the butter overtop and pulse until the mixture resembles coarse crumbs. Drizzle in the water and pulse a few times to loosely incorporate, then dump the dough onto a large sheet of parchment paper and use your hands to press it together into a cohesive mass. Divide in two equal pieces and form each into a disc of about 5 inches wide. Wrap up in parchment paper and refrigerate one disc for 1 hour (and freeze the other one in a freezer bag for another day! You'll thank yourself when that day comes.)
Roll the dough out between two sheets of parchment paper into a 12" circle. Drape the dough into a 9" pie plate and gently press it down into the bottom. Freeze 10 minutes. Preheat oven to 375ºF with a baking stone or sheet placed on the lowest rack.
To make filling, melt butter in a saucepan on medium heat. Remove from burner, stir in the sugar and let cool. Meanwhile, add the buttermilk to a big bowl and whisk in the flour to dissolve. Whisk in the eggs, yolks, vanilla and salt, then the cooled butter mixture.
Arrange half of the strawberries over the bottom of the pie crust, then pour the filling mixture overtop. Bake on the preheated baking stone until the top is golden brown and the middle has just a bit of jiggle (as everyone's middle should), about 45-50 minutes. If the crust or top are getting dark before the filling is set, tent loosely with aluminum foil. Cool on a wire rack and serve at room temperature topped with remaining berries. Refrigerate remaining pie for up to 2 days.