Mix flour and powdered sugar together, then pour the butter over the dry ingredients. Mix together gently, until just crumbly. Lightly spray a 9 x 13″ casserole pan (metal with straight sides is best for this) with cooking spray, and then press the crumbs firmly into the pan in an even-ish layer. I like to leave little bumps from my fingers- gives it a rustic texture, but you can do whatever you want. (I also like a thick crust, so if you like it thinner, don’t use all the mix, or make two pans) Bake for 15 minutes at 350.
While that’s baking, make the lemon curd:
6 whole eggs
3 cups white sugar
1 1/2 teaspoons baking powder
1/2 cup flour
1/3 cup FRESH lemon juice. NO skimping with frozen or the squeezie lemon on this one. Don’t do it.
the outer yellow zest from 2 or 3 lemons.
In bowl (I use the same one I made the crust in, just rinsed out) whip the six eggs with a whisk until they are uniform and light. Add the sugar, baking powder and flour, and stir to combine well. With a microplane or small grater, zest only the outer yellow skin from two of your fresh, washed lemons. Probably about 2 Tablespoons. Add tot he egg/sugar mixture. Squeeze the lemons, straining out the pips and pulp, and add the 1/3 cup of juice.
After 15 minutes, pull the crust from the oven, and immediately pour the curd mixture over the hot crust, scraping the bowl to get all the lemony goodness. Pop it back in the over for 45 minutes, or until set and it doesn’t jiggle in the center.
Let cool COMPLETELY (it will be a mess if you rush it, trust me!) before slicing into neat squares. Dust with powdered sugar, and watch your knees give out as you taste them.