Instead of pouring a wet batter on top of a par-baked crust, I make a lemon curd on the stove top and then pour it over the partially baked crust. Then it bakes for a short time to set the top and finish cooking the crust.
I know it’s an extra step, but trust me, its worth it.
2 C. all-purpose flour
1/2 C. powdered sugar
1 C. Butter, cut into cubes and semi-softCurd FILLING
7 large egg yolks
2 large eggs
1 C. + 2 T. sugar
2/3 C. lemon juice (from about 4-5 medium lemons), strained
1/2 teaspoon salt
4 T. unsalted butter, cut in to 4 pieces
3 T. heavy creamFor the crust
Preheat the oven to 350 degrees.
Put the flour and powdered sugar in a food processor and process briefly, about 2 seconds. Add the butter pieces and process to blend, 8 to 10 seconds, then process until the mixture is pale yellow and resembles coarse meal, about three 1-second pulses. Sprinkle the mixture into a 9×13 pan and press firmly with your fingers into an even layer over the entire pan bottom.
Bake the crust until the edges start to brown, about 23 minutes. Remove from oven and set aside.
For the filling
In a medium saucepan whisk together the egg yolks, whole eggs and sugar until combined. Add the lemon juice and salt and whisk until well combined, about 30 seconds.
Add the butter pieces and cook over medium-low heat, stirring constantly with a whisk, until the curd thickens, about 6 minutes.
Stir in the heavy cream and then pour the curd into the warm crust.
Bake until the filling is shiny and opaque and the center 3 inches jiggle slightly when shaken, about 10 minutes. Let the bars cool. Cut into 2 inch squares, wiping the knife blade clean between each cut. Sieve powdered sugar over the bars, if you prefer.