Add the flour, sugar, and salt to a food processor and pulse a few times to combine. Scatter in the cold, cubed butter and pulse in short bursts until the mixture looks like coarse crumbs. Keeping the butter cold here is the secret to a flaky, layered crust.
Drizzle in the vodka and pulse two or three times, then add the ice water a tablespoon at a time until the dough just clumps together when pressed. Don't overwork it, or the crust will turn tough instead of tender and flaky.
Divide the dough into two discs, wrap them in plastic, and refrigerate for at least an hour.
On a lightly floured surface, roll each disc out to about 1/8-inch thickness. Use a pizza cutter to slice even 3×4-inch rectangles, aiming for an even number so every bottom piece has a matching top.
Lay half the rectangles on your parchment-lined baking sheet and brush the edges with beaten egg yolk. Spoon about 2 tablespoons of lemon curd into the center of each, leaving a clean half-inch border all around so nothing leaks out.
Top each filled rectangle with a second piece of dough and press the edges firmly, then crimp with a fork to lock in the filling. Poke a few small vent holes on top so steam can escape without cracking the crust open.
Brush the tops with the remaining egg wash and bake at 375°F for 22 to 25 minutes, until the pastry is deeply golden and the edges are crisp. Let the pop tarts cool completely on a wire rack before glazing.
Whisk together the powdered sugar and lemon zest, then add the lemon juice a little at a time until you get a thick but pourable glaze. Drizzle it generously over the cooled pop tarts and let it set for about 15 minutes before serving.