Instructions

  1. Position rack in lower third of oven and preheat oven to 350°.
  2. Spray pan lightly with vegetable oil spray.
  3. Make the crust: Stir the 3/4 cup of flour, the cornmeal, salt and baking soda together with a whisk to combine; set aside.
  4. In a medium mixing bowl, beat the butter until creamy.
  5. Add 1/3 cup of the sugar and beat at high speed for about one minute or until mixture loses its crumbly texture and begins to form a mass.
  6. Beat in the egg yolk, yogurt and vanilla.
  7. Add the dry ingredients and beat on low speed just until combined--scrape the bowl and beater.
  8. Knead the mixture briefly with your hands to mix thoroughly.
  9. Press the dough evenly into the pan and prick all over with a skewer or fork.
  10. If pan is lightweight, place on baking sheet.
  11. Bake until brown on top, about 20-25 minutes.
  12. Make the topping: Whisk eggs and the egg white with the remaining sugar until combined.
  13. Whisk in the lemon juice and zest.
  14. Whisk in the 1/4 cup of flour.
  15. When crust is golden, reduce oven temperature down to 300°.
  16. Pour topping over hot crust and bake 15-20 minutes, or until topping barely jiggles in the center when you shake the pan gently back and forth.
  17. Cool on a rack.
  18. Chill before cutting into squares.