It’s hard to be alive in 2018 and not come across the technique of ombre in one way or another. Not that the technique is anything new, but ombre – the French term for the gradual fading of one color into another – has steadily found a place in trends from fashion, to beauty, and of course food. I won’t deny that when done well, the ombre cake is a thing of beauty, which is certainly why it’s so instafamous. The nice thing is, it really isn’t hard to do, so we’re going to take a crack at it today.
We’ll be using food color (duh) to create the color changing effect for our cake, but more specifically I recommend a gel food color. The food color you get at the grocery store is mostly water, and because of that it doesn’t always blend well into high fat foods like icing or cake batter. Gel food color has been mildly thickened and stabilized, and it mixes into food product really well.
The easiest and most efficient way to make this cake is by using several sheet pans at once. This may require you to buy some more sheet pans (you’ll need a total of five, quarter sheet pans), but I don’t think that’s a bad idea. For one thing, they’re really cheap. For another, they have many uses and even if you make this cake once and once only (doubtful), you’ll still get plenty of use from the pans. The alternative is to make this cake in several small batches which in my opinion takes up too much time.
Although I don’t usually include yields (to the frustration of some of you I’m sure) this cake requires some measuring for the layers, so I felt a yield was appropriate. The recipe is formulated to give you a 6-8” cake with five layers of cake, each layer at 500g of batter. The total quantity of cake batter is 2.5k, which for any of you using a 5qt. stand mixer will be the absolute capacity max. I tend to finish the batter by hand in a large mixing bowl.
lemon lime ombre cake
vanilla sponge cake
455g butter unsalted
370g whole egg about 7-8 eggs
324g whole milk
60g sour cream
48g vanilla extract
540g cake flour
16g baking powder
Before getting started, bring the butter, egg whites, whole milk, and sour cream to room temperature.
Combine the butter, vanilla extract and sugar and cream them in a stand mixer with a paddle attachment.
Combine the whole eggs and whole milk. Combine and sift the dry ingredients.
Alternately add the wet and dry ingredients to the butter mixture in three additions. With each addition, mix the batter on medium speed for about 4-5min. The air incorporated into the batter during this mixing time will improve rise during baking.
Color the full quantity of batter yellow, and spread 500g of the yellow batter into one of your quarter sheet pans lined with parchment paper or a non-stick baking mat.
Add a small amount of green gel color (very small!) to the remaining batter and mix well. Spread 500g of that batter into the next quarter sheet pan. Repeat this process, adding a little more green color to the batter for each sheet pan, until the fifth and final sheet pan has lime green batter.
Bake the cake at 330F/165C for 10 – 15min., rotating the sheet pans half way through baking.
345g butter unsalted
700g powdered sugar
6g lemon zest
30g lemon juice
30g heavy cream
6g vanilla extract
3g lemon oil
Combine all of the ingredients in a stand mixer with a paddle attachment.
Mix the ingredients on medium speed until light in body and smooth.
key lime custard
176g whole egg about 3-4 eggs
157g egg yolk about 8 eggs
275g key lime juice
167g butter unsalted
Add the butter to a heat safe mixing bowl or container and reserve to use later.
Heat the key lime juice in a sauce pot over medium-high heat until just simmering.
While the key lime juice is heating, combine the whole eggs, egg yolk, and sugar, whisking well until fully homogenized.
Remove the key lime juice from the heat and pour the egg mixture into the juice, whisking rapidly.
Return the mixture to the heat and cook, whisking continuously, over medium heat to 180F/82C.
Remove from the heat and continue to whisk for 30 seconds to 1min. This additional whisking will prevent any carryover heat from curdling the mixture.
Add the butter to the curd, and whisk or hand blend until smooth and glossy.
Cover the custard with plastic wrap to touch (leaving a gap of air on the custard or leaving it completely uncovered will cause the top layer of custard to dehydrate and form a skin), chill in the refrigerator for several hours until fully cooled and set.
Cut the cooled sponge cake, using a cake ring as a template for each round. Save the extra cake to use as decoration.
Smooth the key lime custard and lemon frosting separately with a spatula. Reserve the key lime custard to use later, and place the lemon frosting in a piping bag with a 8-9mm round piping tip.
Start with the green cake as the bottom layer, pipe a ring of lemon frosting around the outer edge of the sponge.
Add the key lime custard to the layer of cake, inside the ring of frosting. Smooth the custard with an offset spatula.
Repeat this process, adding each layer of cake in order from green to yellow.
Cover the cake in plastic wrap to keep it from drying out and place it in the freezer for 5-10min. to allow the frosting to firm up.
Add a thin layer of frosting around the cake to create a crumb coat. I start with a large amount of frosting on top that I spread thin with an offset spatula allowing the frosting to work over the edges of the cake. Use the offset to spread the frosting around the side of the cake, then use a bench scraper to smooth the sides. Back to the offset spatula, carefully strike the edges clean, working from the outer edge of the cake toward the center. Place it back in the freezer, without plastic wrap, for 10-15min.
Add a second, thicker layer of frosting for a finishing coat, repeating the general process from the crumb coat.
I chose to decorate the cake with quenelles of vanilla frosting, lemon slice, and pieces of the leftover cake. I crumbled some of the leftover cake to use around the bottom edge, too. Don’t forget to take a minute after you cut the cake to bask in ombre glory!
Cheers – Chef Scott