Paula Deen's recipe for Key lime cake contains 2 tablespoons key lime zest, three eggs, 3 cups of cake flour, 3/4 cup of softened butter, and 1 3/4 cups of sugar. Also included are 1/4 cup fresh Key lime juice, 1 teaspoon baking soda and 1 1/2 cups of buttermilk.
Grease and flour three 9-inch cake pans, then preheat the oven to 340 degrees Fahrenheit. Use an electric beater at medium speed to mix the butter, sugar and lime zest in a large bowl until creamy. Add the eggs one at a time, and make sure one egg is well incorporated before adding another. Beat in the lime juice until well mixed.
Mix the cake flour and baking soda in a medium bowl, then sift. Add gradually to the butter mixture. Alternate with the buttermilk, and make sure to begin and end with the flour mixture.
Pour the batter into the pans and bake for 18 to 20 minutes or until a toothpick inserted in the center of each cake comes out clean. Let the cakes cool in the pans for about 10 minutes, then turn them out on wire racks to cool completely. Spread frosting in between the layers, on the sides and on the top, then garnish with wedges of Key lime.