224 grams (2 sticks) unsalted butter, room temperature, plus more for pans
384 grams unbleached all-purpose flour, plus more for pans
3/4 teaspoon kosher salt
1/2 teaspoon baking soda
2 tablespoons finely grated lemon zest (from 2 lemons), plus 4 tablespoons fresh lemon juice
400-500 grams granulated sugar
6 large eggs
1 teaspoon pure vanilla extract
1 cup sour cream
Candied Lemon Slices and Lemon Syrup
256 grams confectioners' sugar
Total time: 4h
Preheat the oven to 350 F (176 C), butter and lightly flour two loaf pans. In a medium bowl, whisk together flour, salt, baking soda, and lemon zest, set aside.
In a large bowl, using an electric mixer on high speed, beat butter and granulated sugar until light and fluffy. Add eggs one at a time, beating well after each addition; mix in vanilla. With mixer on low, alternately add flour mixture in three parts, and sour cream in two, beginning and ending with flour mixture.
Divide batter between prepared pans; smooth tops. Bake until a toothpick inserted in center of cakes comes out clean, 55 to 65 minutes (tent loosely with foil if browning too quickly). Meanwhile, make Candied Lemon Slices and Lemon Syrup.
Remove cakes from oven; while they're still in pans, use a wooden skewer or toothpick to poke several holes in tops. Setting aside 1/4 cup Lemon Syrup, pour remainder over cakes. Let cakes cool completely in pans, about 2 hours. Remove from pans, and place, right side up, on a rack set over a rimmed baking sheet. Brush cakes all over with reserved syrup.
In a small bowl, whisk confectioners' sugar with 2 tablespoons lemon juice; add up to 2 more tablespoons juice until pourable but thick.
Pour lemon glaze over cakes (still on cooling rack), letting it drip down the sides. Let set, about 30 minutes. Garnish with Candied Lemon Slices.
200 grams sugar
2 lemons, sliced 5mm thick or thinner
80 mL to 118 mL lemon juice
In a medium saucepan, combine sugar and 1 cup water; bring to a boil, stirring to dissolve sugar.
Add lemon slices, and simmer very gently over medium-low heat, swirling pan occasionally, until slices are opaque throughout, 20 to 30 minutes.
With a slotted spoon, transfer slices to a sheet of waxed paper; set aside. Add juice to pan, stir, and set aside.