Begin this cake one day ahead. The cake layers need to chill in the refrigerator overnight. Be sure to use the spoon and sweep method for measuring flour, so the cake isn’t too dense – or use a scale to be sure.
12maraschino cherries with stemsdrained on paper towels
Preheat the oven to 350°F. Coat four 6-inch round cake pans with flour-based baking spray.
Cream together the butter and sugar in the bowl of an electric stand mixer fitted with the whip attachment. When the mixture is fluffy, gradually add the oil. Beat until combined. Add eggs one at a time and beat well after each addition.
In a separate mixing bowl, combine the flour, salt, and baking powder. Whisk well to aerate and combine. Pour the dry mixture into the creamed mixture. Beat until just combined. Add the lemon extract and mix again; Pour in 3/4 cup of the 7UP and beat until well incorporated.
Divide the batter between the prepared pans, about 2 cups of batter per each 6-inch pan. Bake for 30-40 minutes, or until the cakes are well browned on top and set in the center. These cakes should not dome much due to the high sugar content.
Transfer cakes to wire cooling racks to cool completely. Wrap cakes in plastic wrap and transfer to the refrigerator to chill overnight.
Unwrap cakes and conservatively trim off the crusty tops. The cakes will be very firm chilled. Place cakes in a large baking pan and poke holes in each using a skewer. Pour over the remaining soda. Transfer to the refrigerator and allow the cakes to soak while you prepare the frosting. Note: Don’t let cakes soak for too long, or they will start to break down. You want to start building the cake within about 30 minutes.
Lemon Lime Buttercream
Cream together the butter and sugar in a standing mixer fitted with the whip. Add milk or cream to bring to piping consistency. Whip for 4 minutes, until the mixture lightens considerably in color. Add the lemon extract; beat well. Transfer 3/4 of the frosting to a separate bowl and cover with a damp towel. Divide the remaining frosting into separate bowls and tint one bowl with the yellow food color; tint the other bowl with the leaf green food color and stir in the lime extract. Transfer each color of frosting to separate piping bags with the ends snipped. Also transfer 1 1/2 cups of white frosting to a piping bag with the end snipped.
Place a cake layer on a cake board, serving plate, or cake stand. Do this gently and carefully, because the cakes will be soft from the 7UP soak. Top with a generous 1/4 cup of the white frosting from the covered bowl and spread gently and evenly. Stack a second cake layer on top. Repeat process until all of the cakes are filled and stacked. Pipe white frosting around the entire outside of the cake and smooth using a bench scraper or cake smoother. Transfer to the refrigerator to chill, about 20 minutes. Remove from the refrigerator and pipe green frosting 1/3 of the way up the cake, followed by a section of white frosting another 1/3 of the way up, and end with yellow frosting covering the final 1/3 of the cake. Smooth frostings together on the sides of the cake using a bench scraper or cake smoother; don’t smooth the top yet. Immediately toss yellow sprinkles on to the green part of the cake; toss green sprinkles onto the yellow part of the cake. Smooth the top of the cake, trapping some of the green sprinkles in the frosting on top of the cake.
Cut each lemon jelly slice into three triangles; press into the frosting around the bottom edge of the cake. Use leftover lemon-yellow frosting to adhere them if they don’t stick naturally.
Transfer any leftover white frosting in the bowl to a piping bag fitted with a large star decorator piping tip. Pipe about 12 swirls of frosting on the top edge of the cake; top each swirl with a maraschino cherry. Slice cake while slightly chilled for neatest slices. Bring to room temperature before enjoying.
Keyword 7UP soda, layer cake, lemon lime cake, soda pop