Passion fruit, chocolate, and coffee is one of my favorite flavor trios. Though the combo sounds a little out there, it’s actually beloved in lots of pastry kitchens. I wanted a way to feature it in a mainstream dessert. Turns out a deep vanilla chocolate chip layer cake is the perfect fit.
To prepare the chocolate chip layer cake:
1. Put a piece of parchment or a Silpat on the counter. Invert the cake onto it and peel off the parchment or Silpat from the bottom of the cake. Use the cake ring to stamp out 2 circles from the cake. These are your top 2 cake layers. The remaining cake “scrap” will come together to make the bottom layer of the cake.
Layer 1, the bottom
2. Clean the cake ring and place it in the center of a sheet pan lined with clean parchment or a Silpat. Use 1 strip of acetate to line the inside of the cake ring.
3. Put the cake scraps inside the ring and use the back of your hand to tamp the scraps together into a flat even layer.
4. Dunk a pastry brush in the passion fruit puree and give the layer of cake a good, healthy bath of half of the puree.
5. Use the back of a spoon to spread half of the passion fruit curd in an even layer over the cake.
6. Sprinkle half of the chocolate crumbs evenly over the passion fruit curd. Use the back of your hand to anchor them in place.
7. Use the back of a spoon to spread one-third of the coffee frosting as evenly as possible over the chocolate crumbs.
Layer 2, the middle
8. With your index finger, gently tuck the second strip of acetate between the cake ring and the top 1/4 inch of the first strip of acetate, so that you have a clear ring of acetate 5 to 6 inches tall — high enough to support the height of the finished cake. Set a cake round on top of the frosting, and repeat the process for layer 1 (if 1 of your 2 cake rounds is jankier than the other, use it here in the middle and save the prettier one for the top).
Layer 3, the top
9. Nestle the remaining cake round into the frosting. Cover the top of the cake with the remaining frosting. Give it volume and swirls, or do as we do and opt for a perfectly flat top. Garnish the frosting with the mini chocolate chips.
10. Transfer the sheet pan to the freezer and freeze for a minimum of 12 hours to set the cake and filling. The cake will keep in the freezer for up to 2 weeks.
11. At least 3 hours before you are ready to serve the cake, pull the sheet pan out of the freezer and, using your fingers and thumbs, pop the cake out of the cake ring. Gently peel off the acetate, and transfer the cake to a platter or cake stand. Let it defrost in the fridge for a minimum of 3 hours. (Wrapped well in plastic, it can be refrigerated for up to 5 days.)
12. Slice the cake into wedges and serve.
To make the chocolate chip cake:
1. Heat the oven to 350 degrees F.
2. Combine the butter and sugars in the bowl of a stand mixer fitted with the paddle attachment and cream together on medium-high for 2 to 3 minutes. Scrape down the sides of the bowl, add the eggs, and mix on medium-high again for 2 to 3 minutes. Scrape down the sides of the bowl once more.
3. On low speed, stream in the buttermilk, oil, and vanilla. Increase the mixer speed to medium-high and paddle for 4 to 6 minutes, until the mixture is practically white, twice the size of your original fluffy butter-and-sugar mixture, and completely homogenous. Don’t rush the process. You’re basically forcing too much liquid into an already fatty mixture that doesn’t want to make room for the liquid. Stop the mixer and scrape down the sides of the bowl.
4. On very low speed, add the cake flour, baking powder, and salt. Mix for 45 to 60 seconds, just until your batter comes together and any remnants of dry ingredients have been incorporated. Scrape down the sides of the bowl. If you see any lumps of cake flour in there while you’re scraping, mix for another 45 seconds.
5. Pam-spray a quarter sheet pan and line it with parchment, or just line the pan with a Silpat. Using a spatula, spread the cake batter in an even layer in the pan. Give the bottom of your sheet pan a tap on the countertop to even out the layer. Sprinkle the chocolate chips evenly over the cake batter.
6. Bake the cake for 30 to 35 minutes. The cake will rise and puff, doubling in size, but will remain slightly buttery and dense. At 30 minutes, gently poke the edge of the cake with your finger: the cake should bounce back slightly and the center should no longer be jiggly. Leave the cake in the oven for an extra 3 to 5 minutes if it doesn’t pass these tests.
7. Take the cake out of the oven and cool on a wire rack or, in a pinch, in the fridge or freezer (don’t worry, it’s not cheating). The cooled cake can be stored in the fridge, wrapped in plastic wrap, for up to 5 days.
Tip: There is a ton of liquid and fat in this amazing cake! If you do not do your due diligence to make sure that the batter is homogenous at each step (no streaks, discolorations or other signs of separation/unincorporation), you’ll be sorry when your cake bakes out of its pan and all over the bottom of your oven.
To make the passion fruit curd:
1. Put the passion fruit puree and sugar in a blender and blend until the sugar granules have dissolved. Add the eggs and blend on low until you have a bright-orange-yellow mixture. Transfer the contents of the blender to a medium pot or saucepan. Clean the blender canister.
2. Bloom the gelatin. (See below.)
3. Heat the passion fruit mixture over low heat, whisking regularly. As it heats up, it will begin to thicken; keep a close eye on it. Once it boils, remove it from the stove and transfer it to the blender. Add the bloomed gelatin, butter, and salt and blend until the mixture is thick, shiny, and super-smooth.
4. Transfer the mixture to a heatproof container, and put in the fridge until the curd has cooled completely, at least 30 minutes. The curd can be refrigerated for up to 1 week; do not freeze.
Tip: Powdered gelatin can be substituted for the gelatin sheets: use 1/2 teaspoon.
Blooming gelatin: Get it right, or do it twice
In order to incorporate it seamlessly into a mixture, gelatin must be softened, or “bloomed,” first. To bloom any amount of sheet gelatin, soak it in a small bowl of cold water. The gelatin is bloomed when it has become soft, after about 2 minutes. If the gelatin still has hard bits to it, it needs to bloom longer. If it is so soft it is falling apart, it is overbloomed; discard the gelatin and start over.
Gently squeeze the bloomed gelatin to remove any excess water before using.
To bloom powdered gelatin (any amount between 1/2 teaspoon and 2 teaspoons), sprinkle it evenly onto the surface of 2 tablespoons of cold water in a small cup. If you pour the powdered gelatin into a pile on top of the water, the granules in the center will remain hard and will not bloom. If you use too much water to bloom the gelatin, it will dilute the flavor of the recipe and its consistency will be looser than intended. Allow the granules to soften entirely in the cold water for 3 to 5 minutes. Once it is bloomed, in order to incorporate either kind of gelatin into a mixture, you need to dissolve the gelatin in hot, but not boiling, liquid — usually a bit of whatever it will be mixed into. If the gelatin gets too hot, it will lose its strength and you will have to start over again.
To make the coffee frosting:
Do not make this recipe until you are ready to assemble the chocolate chip cake. Once it is cold, coffee frosting is hell to bring back up to room temp. It will separate on you, and you will spend the same amount of time trying to force the coffee milk back into the butter mixture.
1. Combine the butter and confectioners’ sugar in the bowl of a stand mixer fitted with the paddle attachment and cream together on medium-high for 2 to 3 minutes, until fluffy and pale yellow.
2. Meanwhile, make a quick coffee milk: Whisk together the milk, instant coffee, and salt in a small bowl.
3. Scrape down the sides of the bowl with a spatula. On low speed, gradually stream in the coffee milk. You are essentially forcing liquid into fat, so be patient. The butter mixture will clump up and separate upon contact with the coffee milk. Do not stream more coffee milk into the butter mixture until the previous addition is fully incorporated; keep the mixer on and remain patient. The result will be a wildly fluffy coffee frosting, pale brown and super-shiny.
Tip: We use Nescafe instant coffee for this delicious frosting.