1 3/4 cups sugar
3/4 cup (1 1/2 sticks) unsalted butter, room temperature
2 tablespoons grated lemon peel
3 extra-large eggs
1/4 cup fresh lemon juice
3 cups cake flour
1 teaspoon baking soda
1/4 teaspoon salt
1 1/2 cups buttermilk
Position rack in center of oven and preheat to 350°F. Butter and flour three 9-inch-diameter cake pans with 1 1/2-inch-high sides. Beat sugar, butter and lemon peel in large bowl until light and fluffy. Add eggs 1 at a time, beating well after each addition. Beat in lemon juice. Sift flour, baking soda and salt into medium bowl. Stir dry ingredients into butter mixture alternately with buttermilk, beginning and ending with dry ingredients.
Divide batter among prepared pans. Bake until tester inserted into center of cakes comes out clean, about 30 minutes. Transfer pans to racks and cool 15 minutes. Turn out cakes onto racks and cool completely. (Can be prepared 1 day ahead. Wrap tightly in plastic and store at room temperature.)
Ina Garten's Lemon Curd
1 1/2 cups sugar
1 stick (4 oz) unsalted butter, room temperature
4 extra-large eggs
1/2 cup lemon juice (3 to 4 lemons)
1/8 teaspoon kosher salt
Using a carrot peeler, remove the zest of 3 lemons, being careful to avoid the white pith. Put the zest in a food processor fitted with the steel blade. Add the sugar and pulse until the zest is very finely minced into the sugar.
Cream the butter and beat in the sugar and lemon mixture. Add the eggs, 1 at a time, and then add the lemon juice and salt. Mix until combined. Pour the mixture into a 2 quart saucepan and cook over low heat until thickened (about 10 minutes), stirring constantly. The lemon curd will thicken at about 170 degrees F, or just below simmer. Remove from the heat and cool or refrigerate with a layer of plastic wrap directly on the surface.