Ingredients

  • 2 cups all-purpose flour plus more
  • 1 teaspoon kosher salt
  • 1 teaspoon sugar
  • 3/4 cup (1 1/2 sticks) chilled unsalted butter cut into 1/2" cubes
  • 1/2 cup (or more) cold buttermilk
  • 1 1/2 cups sugar
  • 1/2 cup (packed) light brown sugar
  • 1 1/2 tablespoons yellow cornmeal
  • 1 tablespoon all-purpose flour
  • 5 large eggs, beaten to blend
  • 2/3 cup buttermilk
  • 1/2 cup (1 stick) unsalted butter, melted
  • 1 3/4 tablespoons fresh lemon juice
  • 1 tablespoon freshly grated lemon zest
  • 2 teaspoons vanilla extract
  • Pinch of kosher salt
  • A 9 1/2"-diameter deep-dish pie pan

Method

  • Mix flour, salt, and sugar in a food processor. Add butter; pulse until pea-size pieces of butter form. Add 1/2 cup buttermilk; pulse until moist clumps form, adding more buttermilk by tablespoonfuls if too dry. Form into a ball; flatten into a disk. Wrap in plastic and chill for 1 hour.
  • Preheat oven to 350°F. Roll out dough on a lightly floured surface to a 14" round. Transfer to pie pan; gently press onto bottom and up sides of pan. Trim dough, leaving a 1" overhang; tuck overhang under. Crimp edges decoratively. Line with parchment paper or foil; fill with pie weights or dried beans.
  • Bake crust until edges begin to brown, 30-35 minutes. Remove paper and weights; bake until golden brown, 25-30 minutes longer. Let cool completely.
  • Preheat oven to 350°F. Whisk first 4 ingredients in a medium bowl until well combined. Whisk eggs and remaining 6 ingredients in a large bowl (mixture may look curdled). Slowly whisk in dry ingredients. Pour filling into cooled crust and bake until custard is set around edges but jiggles slightly in center, 1 hour-1 hour 15 minutes. Let cool completely on a wire rack. DO AHEAD: