- 1 cup (2 sticks) unsalted butter, room temperature, plus more for pans
- 2 1/2 cups all-purpose flour (spooned and leveled), plus more for pans
- 1/2 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1 teaspoon salt
- 1 tablespoon lemon zest
- 1 1/2 cups sugar
- 2 large eggs plus 3 large egg yolks
- 2 tablespoons fresh lemon juice
- 1 cup low-fat buttermilk
- 1/2 cup sugar
- 1/2 cup water
- 1/4 cup lemon juice
- 1 lemon, thinly sliced and seeded
- 1 cup cold butter
- 3 3/4 cups confectioners’ sugar
- 1 lemon, zested and juiced
- 1 teaspoon vanilla extract
- 1/8 teaspoon salt
Preheat oven to 350 degrees. Butter and flour two 8-by-2-inch cake pans, tapping out excess flour. In a medium bowl, whisk flour, baking powder, baking soda, salt, and lemon zest.
InÂ a large bowl, using an electric mixer, beat butter and 1 1/2 cups sugar until light and fluffy. With mixer on low, beat in eggs and yolks, one at a time. Beat in 2 tablespoons lemon juice. Alternately beat in flour mixture and buttermilk beginning and ending with flour mixture; mix just until combined.
Divide batter between pans; smooth tops. Bake until cakes pull away from sides of pans, 32 to 35 minutes. Let cool in pans 10 minutes. Run a knife around edges of pans and invert cakes onto a wire rack.
While cakes are baking, bring remaining 1/2 cup sugar and 1/2 cup water to a boil in a saucepan. Add lemon slices and simmer 25 minutes. Using a slotted spoon, transfer lemon slices to a waxed-paper-lined plate. Stir remaining 1/4 cup fresh lemon juice into syrup.
Using a toothpick, poke holes in warm cakes on rack. Brush with lemon syrup. Let cool completely.
While cakes are cooling, make frosting.Â Combine butter, sugar and salt and beat until well combined.Â Add lemon juice, zest, and vanilla and continue to beat for another 3 to 5 minutes or until creamy.
Frost cooled cakes and top with candied lemon slices.