The ingredients for a key lime cake from scratch on Food.com include butter, sugar, key lime zest, eggs, key lime juice, cake flour, baking soda and buttermilk. This recipe also includes a white chocolate frosting with white chocolate, whipped cream, butter, vanilla and confectioner's sugar.
To make the recipe, preheat your oven to 340 F and grease and flour three 9-inch cake pans. Beat the butter, sugar and lime zest with an electric mixer until smooth. Beat in 3 eggs one at a time, the beat in the key lime juice until combined.
Combine the cake flour and baking soda together in a bowl. Add the dry ingredients alternately with the buttermilk into the butter mixture. Pour into the cake pans and bake for 18 to 20 minutes. Let the cakes cool in the pans for 10 minutes before removing to cool completely on wire racks.
To make the frosting, microwave the white chocolate and cream in a bowl in 30-second intervals until melted. Let this mixture cool and then combine with the butter and vanilla in a large bowl and beat on medium until combined. Slowly mix in the confectioners' sugar. Spread the frosting on the top and sides of each cake. If you wish, garnish with key lime wedges.