• Preheat the oven to 350F and butter a 11 3/4-by-7-inch glass or ceramic baking pan (if you only have a 9x13, that will work, but the bars will be less thick)

Crust:

• To make the crust, add the powdered sugar into the bowl of a stand mixer fitted with the paddle attachment. Stir in the flour. Add the butter and vanilla bean paste and beat on low speed until a smooth dough forms.
• Press the dough evenly into the pan using a piece of plastic wrap to help smooth the dough evenly. Line the crust with parchment paper and fill with baking weights.
• Bake the crust until it is a deep golden brown, about 40 minutes. Bake for the first 30 minutes with the pie weights. After 30 minutes, remove from the oven and remove the pie weights and parchment. Place the crust back into the oven for an additional 10 minutes until lightly golden (adjust the total bake time to 30-35 minutes if using a 9x13)

Filling:

• To make the filling, while the crust is baking, sift the flour into a mixing bowl and whisk in the sugar until blended. Add the lemon juice and zest and stir to dissolve the sugar. In a separate mixing bowl, whisk the whole eggs and egg yolk with the salt. (The salt helps to break up the eggs). Then add the eggs to the lemon juice mixture and whisk until well mixed.

Combining:

• Once the crust is ready, pour the filling directly into the pan. Reduce the oven temperature to 300 degrees F. and bake just until the center of the custard is set, about 35 - 40 minutes. (adjust the bake time to 30-40 minutes if using a 9 x 13)
• Let cool completely on a wire rack. Cut into squares and dust the top with confectioners’ sugar. They will keep in an airtight container or well covered in the baking dish for 3-4 days.