Chocolate and orange is such an underrated flavor combination. I always see so many chocolate-strawberry and chocolate-raspberry desserts, but rarely any chocolate-orange desserts. I decided to change that by making this, decadent, citrusy chocolate orange mousse cake. It’s two layers of a chocolate-orange flavored cake with chocolate mousse and orange custard layered in between. It’s topped with orange-flavored icing, chocolate shavings, orange zest, and orange slices. It’s a bit time consuming to make, but completely worth it. It’s eye-catching and it’s absolutely delicious. It’s bound to please every chocolate lover, and the citrusy-chocolate flavor combination may even win over some non-chocolate lovers.
Ingredients
Equipment
Method
Cake:
- Prepare two 9-inch round cake pans by placing parchment paper in them on the bottoms and the sides, and spread some oil onto them to make the parchment paper stick. Also, preheat your oven to 350 degrees Fahrenheit.
- Sift the flour, baking powder, baking soda, and cocoa powder into a large bowl. Mix together.
- Beat the vegetable oil and sugar together with an electric beater on medium speed for a few minutes until well-combined.
- Pour the apple cider vinegar and milk mixture into the oil-sugar mixture. Add in the fresh orange juice, vanilla extract, orange extract, orange zest, chocolate chips, instant ground coffee, and mix well with a spoon.
- Pour the batter into the cake pans.
- Put the pans in the oven and bake for 35-40 minutes. After 35 minutes, poke a toothpick into the cake to see if the cake is ready. If the toothpick is wet, the cake is not yet ready. Bake for a few more minutes, until the toothpick comes out of the cake clean.
- Once the cakes are done, place on a cooling rack. Cool at room temperature overnight, or at least for a few hours. Then, transfer to the fridge for a few hours to let them chill so they can be frosted later.
Orange Custard:
- Whisk together the milk, sugar, orange juice, orange zest and cornstarch. In a small pot or pan, heat the mixture on medium heat until it starts bubbling. This usually takes 3-4 minutes. Add in the butter and whisk until the butter is melted, and then turn off the heat. The custard should be a thick, almost jelly-like consistency. If it’s too liquidy, add more butter. If it’s too thick, add more orange juice or milk.

Chocolate Mousse:
- Blend the silken tofu, chocolate chips, instant coffee, and sugar until smooth. Place in the fridge overnight. It will be very liquidy after blending, but it will solidify as it sits in the fridge.

Chocolate Shavings:
- To make the chocolate shavings, microwave the chocolate chips with the coconut oil. If you don’t have coconut oil, you can use some other type of fat such as butter or shortening. Microwave for a few seconds at a time, making sure to stir in between so that the chocolate doesn’t burn. It usually takes about 30-45 seconds to fully melt, but it may also depend on how powerful your microwave is.
- Once the chocolate is melted, pour into a container and let it freeze until hardened.
- Once the chocolate has hardened, take it out of the freezer and use a vegetable peeler to make the chocolate shavings.

Decorating and assembling the cake:
- For the icing, I used an electric mixer to beat together plant-based butter, icing sugar, shortening, and vanilla extract. I don't remember the exact proportions I used, but there are many vegan icing recipes online you can follow. To make it orange flavored, I added a bit of pure orange extract (1-2 teaspoons), orange zest, and some of the leftover orange custard. I also added a bit of orange food coloring.
- To assemble the cake, place one layer on a cake tray. Spread the chocolate mousse on top and then spread the orange custard on top of that. Place the second cake layer on top. You can frost and decorate the cake, or simply serve it as is.
- If decorating, do a crumb coat with the orange icing we prepped earlier. Put it in the fridge for about 30-40 minutes to let the crumb coat layer set. Then, take it out of the fridge and do another coat of icing to make sure the crumbs from the previous layer are fully covered.
- To decorate the cake, I used a Wilton 1M tip for the white dollops of frosting and a smaller star tip for the orange dollops. I then arranged the orange zest, chocolate shavings, and orange slices as shown in the picture. You can decorate it the same way as I did or any way you’d like!
Notes
- Flour: All-purpose flour will create a more firm cake, while cake flour will create a softer but more crumbly cake. When I made this, I used half parts cake flour and half parts all-purpose flour. It turned out very soft and moist but a bit crumbly, so next time I make it I would probably add a flaxseed-water mixture (or another egg substitute) to help with binding the cake better. You can also use just all-purpose flour instead of half parts all-purpose flour and cake flour if you’d prefer.
- Cocoa powder: I used half parts Dutch-pressed cocoa powder and natural cocoa powder. From my understanding, Dutch-pressed cocoa powder produces a richer chocolate color and flavor and creates a denser and fudgier texture, while natural cocoa creates a lighter, more cake-like texture. It’s up to you which one to use, but I used a mix of them and I thought it turned out perfectly.