So. The most important thing to say about this is that this cake is, IMHO, among the most delicious deserts that can be eaten. It doesn’t taste like a sweet dessert. The lime is wonderfully tart. The pureed mango jelly is summery & fruity. The sponge is gingery and springy despite being soaked with a little extra lime juice for a secret kick.
This cake is super simple.. when you write it out like this:
- Cut a 2 ½" x ¾" disk out of a Genoise Sponge
- Wrap with acetate collar
- Place 1" vertical mango strips against collar
- Pipe diplomat cream to top of mango strips
- Top with mango jelly & a sliver of candied lime peel
Luckily, making these little cakes (or a much larger one, which is far more efficient), it isn’t actually all that hard to make the 3 key ingredients: a genoise sponge, diplomat cream, & mango jelly.
This is about a 3 hour commitment; here’s the breakdown of my time to make 9 of these little cakes on my first attempt. Bare in mind though that the sponge and cream can be made a day (or several) ahead of time making this a fun 2-day baking project:
- sponge — 42 minutes
- cream — 38 minutes
- jelly — 22 minutes
- assembly — 90 minutes
- grand total: ~3hrs
The assembly is where you make or break this baking experience. The best way to do this is just to make a full 9" cake. If you just make one large cake then you only have to make 1 collar, 1 mango arrangement, one piping and one gelatin pouring instead of 9. Easy win. But it’s totally doable to make the personalized version too.
Assembly for Personal Cakes
How special would you feel if someone made you one of these little cakes, right? If you want to flatter some friends, here’s some tips:
#1 Greasy Collars
The diplomat cream can stick to the acetate enough to pull apart, especially if the cake isn’t super cold. Just wipe a little neutral flavored oil (canola, etc) on the collar before assembly.
#2 Slender Strips
The more mango you use, the more actual fruit you get to eat. However, if the fruit extends into the center of the cake, it really complicates piping the cream. If this doesn’t sound bad yet, remember to multiply whatever you’re thinking of by 9x and remember that you’ve only got a 2.5" cylinder of workspace. So make sure to cut the mango a max of ¼"x¼" and 1" tall.
#3 Do the Math
Regardless of whether you go for a single cake or several small ones, make sure you sketch out the heights ahead of time to get the overall cake right. I found that this made a very nice balance of components and aesthetically proportional final bake.
#4 Mango - To the Core!
The one thing I wish I had done was get a little more mango flavor into the cake. The best way to do this would be to include a central column of mango jelly right down the center of the cake. When piping columns of cream along the outside, between the mango strips, leave a space in the center. Then when you pour the mango jelly it will fill the center as well as the top.
The Recipes You’ll Need
Here you go.
#1. Ginger Genoise Sponge
- unsalted butter
- 1 teaspoon
- vanilla extract
- ½ cup sifted cake flour
- 6 tablespoons cornstarch
- 1 tablespoon ground ginger
- 4 large eggs
- ¼ cup finely chopped crystallized ginger
- ½ cup granulated sugar*
- Adjust oven rack to center position and heat oven to 350 degrees. Grease 9-by-2-inch round cake pan. Line bottom with parchment paper; grease paper as well. Dust pan lightly with flour; tap out excess.
- Melt butter in small heavy saucepan over medium heat. When butter looks clear, continue to cook, watching carefully, until solids drop and begin to brown. Immediately pour through fine strainer or strainer lined with cheeses cloth. Return clarified browned butter (there should be 3 tablespoons) to medium bowl, add vanilla, and keep warm by covering.
- Sift flour, cornstarch, and ground ginger together; set aside. Heat eggs and sugar in large mixing bowl set over saucepan of simmering water (do not let the bottom of bowl touch water), stirring constantly to prevent curdling, until mixture reaches 110°F. Remove from heat and, using whisk attachment on standing mixer, beat on high speed until egg mixture triples in volume, about 5–8 minutes.
- Thoroughly whisk scant cup of egg mixture with warm butter and crystalized ginger, set aside. Turn half of flour mixture into sieve, sift over remaining egg batter. Fold gently, but rapidly, with large skimmer or whisk. Repeat with remaining flour, folding until flour is no longer visible. Fold in egg/butter/ginger mixture until just incorporated.
- Immediately pour batter into prepared pan. Bake until cake starts to pull away from sides, 20 to 25 minutes. (Do not open oven door until cake is almost done or it could fall). Meanwhile, grease two cake racks.
- Immediately loosen cake from side of pan with small metal spatula and invert at once onto greased rack. Remove parchment and invert cake again onto second rack. Let cool completely. (Genoise can be wrapped in plastic and stored at room temperature for 2 days, refrigerated for 5 days, or frozen for 2 months).
#2. Lime Syrup
- Juice of 2 limes
- 3 tablespoons sugar
Just heat this up in the microwave gently and whisk until sugar dissolves. Genoise sponges contain very little fat so they can feel pretty dry. You will brush this on the sponge to give it some moisture, and a nice little punch.
#3. Lime Diplomat Pastry Cream
A Diplomat starts with a cream pat base, the standard pastry cream found in eclairs and such pastries. In order to make it a little more stable though, we add a little gelatin. And to make it wonderfully soft, we gently fold in a bit of whipped cream.
- 5 egg yolks
- 1/2 cup sugar
- 1/4 cup cornstarch
- 1/8 teaspoon salt
- 2 cups half and half
- finely grated zest from one lime
- 2 tablespoons lime juice*
- 4 tablespoons unsalted butter
- 1/2 teaspoon vanilla extract
- 1 teaspoon granulated gelatin
- 2 tablespoons tap water
- ½ cup heavy cream
(* Add lime juice concentrate to reach 2 tablespoons if necessary)
- Place strainer over medium bowl. Set aside.
- In medium bowl, whisk together egg yolks, sugar, cornstarch, and salt. Set aside.
- Place half and half and lemon zest in medium saucepan. Cook over medium heat, stirring occasionally until it just bubbles.
- Pour a thin stream of half and half into egg yolk mixture while whisking constantly. Be careful not to pour too quickly or you will scramble the eggs.
- Pour the mixture back into the sauce pan. Whisk constantly over medium heat until the liquid bubbles and thickens. Whisk one more minute.
- Pour cooked cream through strainer into bowl. Whisk in butter, vanilla, and lemon juice.
- Sprinkle gelatin over the tap water evenly to soften. Break up any clumps, then microwave for 10 or 15 seconds to dissolve completely.
- Thoroughly whisk dissolved liquidy gelatin into the stiff and cool pastry cream.
- Whip 1/2 cup cold heavy cream to stiff peaks and fold into the chilled pastry cream, blending thoroughly.
- Place plastic wrap directly on top of cream. Refrigerate until set, at least one hour. Use within 3 days.
#4 Mango Jelly
- 2 cups mango puree
- ½ cup sugar
- 1 cup water
- 1 ½ tablespoons gelatin
- Peel and roughly cube mangoes. Puree in food processor until completely smooth.
- Optionally strain puree through food mill or strainer. This will make a more aesthetically clean jelly, but will not significantly affect texture or flavor.
- Take gelatin in a bowl, cover with 1/4 cup of water. Let soak until absorbed. Heat in microwave briefly until completely dissolved.
- Heat sugar and remaining water in a sauce pan until sugar has melted.
- Add in the gelatin and mango puree. Mix well.
- Cool to room temperature and skim off any skin that has formed before pouring over cream.
#5 Candied Lime Peel (optional)
This is for decoration only, so feel free to skip this step. It doesn’t take long, but these cakes will look fine with just a dollop or piping of diplomat cream, or just a plain top.
- 1 lime, peeled into 1/8" strips
- 2 cups sugar
- 1 cup water
- Fine granulated sugar for coating
- Boil the peels in a pot of water for 5 minutes. Drain the peels in a colander, rinse and then drain again. Discard the water from the pot. This process reduces the bitter flavor, so repeat 1–2 more times if you like.
- Add the 1 cup of fresh water and the sugar to the pot and bring it to a boil. Boil it for a couple of minutes until the sugar is dissolved. Add the citrus peels, reduce the heat to low and simmer for 45–60 minutes, stirring occasionally, until the peels become translucent and the syrup becomes lightly syrupy (on a candy thermometer this will be be approximately soft ball stage).
- Use a slotted spoon to remove a few of the peels at a time and let the excess syrup drip off for a few seconds. Place the hot, wet peels in a bowl of sugar or a ziplock bag with sugar in it and toss/shake to coat.
- Place cooled peels on top of finished fraisier cakes