Salted Caramel Squares
Food & Wine
Makes 32 squares (more if you cut them smaller)

Note that this recipe calls for kosher salt in both the crust and the caramel.  Do not substitute table salt – they will be way too salty. I like Diamond Brand.

Pastry Shell
1 stick unsalted butter, softened
1 cup confectioners’ sugar
2 large eggs, beaten
2 cups all-purpose flour
1 tsp. kosher salt
1 large egg white, beaten

Caramel
2¼ cup heavy cream
1 vanilla bean, split, seeds scraped
2¼ cups sugar
1¾ sticks unsalted butter
2½ tsp. kosher salt

Prepare the shell
Preheat the oven to 350ºF.  Line a 9-by-13-inch baking pan with parchment paper, leaving a 2-inch overhang on the short sides.  In a large bowl, using a handheld mixer at low speed, cream the butter.  Beat in the confectioners’ sugar.  Add the whole eggs and beat until incorporated, then beat in the flour and salt.  Press the pastry into the prepared pan in an even layer, ¼-inch thick.  Freeze until firm, 10 minutes.

Line the pastry with parchment paper and fill with pie weights.  Bake for 35 minutes, until just set.  Carefully remove the pie weights and parchment paper.  Brush shell with the egg white and bake for 20 minutes longer, until golden and cooked through.  Let cool.

Make the caramel
In a saucepan, bring the cream, vanilla bean, and seeds to a simmer.  Cover; keep warm.

In a large heavy saucepan, stir the sugar into  ¼ cup of water.  Simmer over moderate heat, without stirring, until a deep amber caramel forms, 7 minutes.

Remove the caramel from the heat and carefully add the cream.  (DT: It will bubble up vigorously so slow as you go.)  When the bubbling subsides, stir in the butter.  Insert a candy thermometer and cook over moderately high heat, stirring with a wooden spoon, until the caramel reaches 240º, 10 minutes.  Discard the vanilla bean and stir in the salt.  Pour the caramel over the shell.  Refrigerate until firm, 4 hours or overnight.  Remove the bar from the pan using the parchment overhang; cut into squares.  (DT:  In my experience, these squares kept well for several days but I did not cut them all at once.  I cut off what I needed and wrapped the rest, carefully, in foil.  They are equally good cold or at room temperature.)