* Preheat oven to 325 degrees.with a rack in the center. Butter a 13-by-9-by-2-inch cake pan. Line bottom and long sides of cake with parchment paper, allowing at least a 1-inch overhang; set aside. In a medium bowl, sift together flour, baking...
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* Preheat oven to 325 degrees.with a rack in the center. Butter a 13-by-9-by-2-inch cake pan. Line bottom and long sides of cake with parchment paper, allowing at least a 1-inch overhang; set aside. In a medium bowl, sift together flour, baking powder, salt, and baking soda; set aside. * In the bowl of an electric mixer fitted with the paddle attachment, beat butter and sugar on medium speed until light and fluffy, 3 to 5 minutes. With the mixer running, add eggs, one at a time, beating to incorporate after each addition. Beat in vanilla, and lemon juice and zest. * With mixer on low speed, add flour mixture, alternating with buttermilk, beginning and ending with the flour mixture, and beating until fully incorporated. * Pour into prepared cake pan. Bake until light golden brown and a cake tester inserted in the center comes out clean, 25 to 30 minutes. Transfer to a wire rack to cool. * Place 3 cups buttercream in a medium bowl, and 1/2 cup in each of 2 bowls. Add sunset orange and... See less 
