Lemon Bars

Method

1. mix8 min
   shortbread: butter + 2 cups flour + 1/2 cup powdered sugar + salt to damp crumbs, pressed into a lined 9x13
   cold butter worked into the dry goods until the mix holds when squeezed — the pie-crust chapter's rubbing motion with a lazier standard — then pressed flat and even into the parchment-lined pan; even is the discipline: thin corners overbake first
2. bake20 min
   350°F, until the shortbread edges just gild
   the par-bake — the crust needs its own head start because the curd bakes gentler and shorter than raw shortbread requires; meanwhile the filling comes together in one bowl
3. mix6 min
   the curd: eggs + sugar whisked, then juice + zest + remaining 1/4 cup flour
   whisked smooth and no further — froth bakes into a pale foam skin on top; the little flour is the set's insurance, and the zest carries the lemon oils that juice alone never delivers
4. bake22 min
   curd poured over the HOT crust, 350°F until the center barely trembles
   poured onto the crust straight from the oven — the weld: hot shortbread grabs the curd and the layers set as one, where a cooled crust sheds its filling at every cut — and baked only until the center wobbles like it might not be done, because it is
5. rest120 min
   fully cold before the knife — then powdered sugar at the last moment
   room temperature, then the fridge, and no negotiating: warm bars cut into lemon rubble, cold ones into clean glass-edged squares (wipe the knife between cuts for the potluck look) — the powdered-sugar snowfall lands at serving time only, since overnight it melts invisibly into the curd and takes the drama with it