Ingredients. 1/2 pound (2 sticks) unsalted butter, at room temperature. 2 1/2 cups granulated sugar, divided. 4 extra-large eggs, at room temperature. 1/3 cup grated lemon zest (6 to 8 large lemons) 3 cups flour. 1/2 teaspoon baking powder. 1/2 teaspoon baking soda. 1 teaspoon kosher salt.