While the mixer is on low speed, slowly pour in the ingredients in the large jug
While the mixer is still running, slowly add the hot water and mix. Your batter will be very thin. Make sure the mixer is on your lowest speed so it doesn't splash everywhere
1 cup hot water
Pour the batter into the prepared pans. Bake for 35-40 minutes, until a toothpick comes out clean when inserted
Allow the cakes to cool completely before removing from pans.
Frosting
Melt your chocolate in a microwave, stirring every 10 seconds so it doesn't burn.
6 oz dark chocolate
In your stand mixer with the paddle attachment, beat the butter and confectioners’ sugar on low speed until well combined.
1 cup unsalted butter, 2 cups confectioners' sugar
Turn the speed to high for 2-3 minutes until light and fluffy.
Add in your cocoa powder and beat on low, then increase the speed to medium for 1-2 minutes.
1 cup cocoa powder
Add your sour cream, melted chocolate, orange juic, orange zest and salt and mix once more.
½ teaspoon kosher salt, ½ cup sour cream, zest of an orange, 2 teaspoons orange juice
Assembly
Once the cakes are both completely cool, you can assemble the layer cake. Place one cake layer on your cake plate or cake stand. Add a large scoop of the chocolate orange frosting on top and spread over the top. Add the second cake layer on top. Apply a thin layer of frosting around the sides and the top of the cake. Place in the fridge or freezer for 15 minutes to set the crumb coat.
Frost the cake with the remaining frosting and enjoy!
Video
Notes
My recipes have been developed and tested in metric grams. I highly recommend using a weighing scale and measuring out your ingredients the metric way. I have provided a conversion to US cups but please note that I haven't tested the recipe with this method. Butter: I use European style butter in my recipes. This will make your cake much creamier and richer.Salt: If you don't have kosher salt, halve the amount of salt called for in the recipe. 1 teaspoon kosher salt = ½ teaspoon fine salt.Storage: Cover the cake tightly and keep in the fridge for up to 5 days. Oranges: if you want a stronger orange flavor you can add more orange zest to both the cake and the frosting. Freezing: Freeze for up to 3 months, let the cake defrost overnight in the fridge and then come to room temperature when you're ready to eat it. Buttermilk: No buttermilk on hand? Mix one tablespoon of lemon juice or white wine vinegar with 1 cup of milk, then let it sit for 5 minutes so it can curdle.