this recipe requires several components. first you will make the orange buttercake. next you will make the lime curd that goes into the lime mousse. it is your choice to candy fresh lime as garnish, as well.
Step 1: The Cake
2 sticks butter
6 oz cream cheese
1 1/3 cup sugar
zest of 1 orange
1 cup flour
2/3 cup self-rising flour
Preheat oven to 350 degrees F.
Line a sheet pan with parchment.
Cream together butter, cream cheese, and sugar until thoroughly combined.
Add in orange zest and eggs. Sift the flours together and add them to batter until just combined.
Pour into sheet pan, using an offset spatula to spread.
Bake for 11 minutes (depending on oven).
Remove from pan and let cool for at least 2 hours before cutting.
Step 2: Lime Curd
2/3 cup sugar
2 tablespoons finely grated lime zest
4 egg yolks
1/2 cup fresh lime juice
1/4 cup fresh lemon juice
4 tablespoons unsalted butter; chilled and cut into 1/2-inch cubes
Combine sugar and lime zest with a fork in a small bowl until very fragrant.
Combine lime sugar, eggs, and egg yolks in a heatproof bowl and whisk together for 30 seconds.
Place the bowl over simmering water and immediately begin whisking, continuing for 15 seconds, until the sugar is dissolved.
Add the lemon and limes juices and cook, whisking continuously for about 5 minutes. Insert a thermometer.
The curd is done when it has a consistency of sour cream and a temperature of 160 degrees F.
Whisk in the butter cubes. Strain through a sieve and set in an ice bath to cool. Cover with plastic film to prevent a skin from forming.
Step 3: Lime Mousse
1 cup lime curd
1 cup heavy cream
Beat cream to stiff peaks.
Incorporate lime curd. Transfer to a piping bag with a plain tip 1/4-1/2" in diameter.
Step 4: Cake Assembly
Using a 3" ring mold as a cutter, cut circles of cake out from sheet cake.
For the first layer in the mold, use cake.
Pipe an even layer of lime mousse on top.
Add another layer of cake and mousse. Repeat until you reach the top of the mold, making sure to end with a mousse layer; smooth the top.
Place molds on a sheet pan in freezer for 1 hour.
Apply pressure from bottom to remove from mold.
[I put candied orange and lime on the top, as well.]