Sour Orange Sponge Cake


Did you know this is the season for sour oranges / bitter oranges or as we call them in Farsi Narenj ? Sour oranges usually have a deep orange colored fruit, are large, and are juicy. They have a thick dimpled skin. Narenj is a fruit that is very dear to most Persians. Even though we don’t eat them as a fresh fruit, we use them in making jam, pastries, scenting teas and herbal medicine and it’s a must to have at Norouz table with our fish and herbal rice or Sabzi-polo Mahi.

Today, I'm sharing my all-time favorite Narenj sponge cake recipe. The incredible orange flavor of the cake pairs extremely well with pastry cream and fresh oranges. We're going to use all the parts of the oranges, from the zest, to the juice and even the seeds. After zesting the oranges, juice them & keep the seeds in a bowl with the juice for couple hours, the pectin in seeds releases and the juice becomes very thick and gives an incredible flavor to the syrup. The intense orange flavor is for those of you who love citrus, I'm sure you’ll be reaching for a second slice. The cake is moist on its own because unlike the traditional sponge cake, it is made with butter which gives the cake not only a delicious flavor but keeps it moist too.

Don't be intimidated by the long process, the cake is easy and you can even make the cake and the pastry cream ahead of time and keep in the fridge or freeze it for up to a month. As usual, I baked one 6" and three 4" cakes and for what you see in the photos is one 6" cake +one 4" cake. I've frozen the other two for another day.

Sour Orange Sponge Cake

Yield: two 9" cakes | Time: 1 hour


  • 125g flour
  • 1 teaspoon baking powder
  • 6 eggs, separated
  • 200g sugar
  • 1 teaspoons vanilla extract
  • Zest of a sour orange; save the juice with all the seeds for later to make the syrup
  • 60g butter, melted


  1. Preheat the oven to 350 degrees. Line two round 9-inch cake pans with parchment paper and spray the center only.
  2. Combine the flour and baking powder and set aside.
  3. Place the egg yolks, 1/2 cup of the sugar and vanilla in a mixing bowl fitted with the whisk attachment. Beat until very pale yellow and very fluffy. 
  4. Place the egg whites in a clean and dry bowl with a clean whisk. Beat until the whisk leaves a trail in the egg whites and the whites are at the soft peak stage. Slowly add the remaining sugar and beat to medium peaks. Do not over beat the whites. Pour the egg yolk mixture and half the flour over the egg whites. Gently fold in. Fold in the remaining flour. Take about 1 cup of batter and whisk into the butter; return this to the main amount of batter and fold in.
  5. Divide the batter equally between the two prepared pans and bake for 20-30 minutes or until lightly browned and the center springs back when lightly touched or a cake tester comes out clean.

Orange Rum Syrup

This same syrup with the coffee was used with the Chocolate Mocha Cake

Sour orange juice; take out the seeds and use the juice

  • 1/4 cup water
  • 1/4 cup sugar
  • 1 tablespoons dark rum
  • 1 teaspoon vanilla extract

Once you juiced the orange, keep the seeds in a bowl with the juice for couple hours, what happens is the pectin in seeds releases and the juice becomes very thick as if you have added gelatin to the juice. In a medium saucepan combine the sugar with juice and water and bring to boil, let it boil for 1 minute, remove from the heat and stir in the rum and vanilla.

Pastry Cream:


  • 1 gelatin sheet or 1 1/2 teaspoon of gelatin powder mixed in with 2 teaspoons cold water
  • 1 1/3 cup milk, very hot
  • 4 egg yolks
  • 100g sugar
  • 35g flour
  • 1 teaspoon vanilla extract
  • 2 tablespoons butter
  • Zest of 1/2 an orange


  1. Bloom the gelatin: break the sheet into 3 pieces, place in a bowl and cover with cold water and set aside until you prepare the cream.
  2. In a medium saucepan, bring the milk to boil
  3. Whisk the egg yolks and sugar together in a heat resistant bowl. Whisk in the flour.  Add the milk slowly, whisking well and scraping the corners of the bowl with a rubber spatula to make sure all of the egg yolk mixture is incorporated. Place over medium heat and, stirring constantly, bring to a boil. Boil for 1 minute, stirring constantly.
  4. Remove from the heat and add the vanilla, orange zest, remove gelatin from water and give it a squeeze to get the excess water out and add to the mixture. Mix until incorporated, Add the butter and whisk to melt.  Pour into a shallow depth dish and covered the top with a plastic wrap and place in the refrigerator until the cake is ready.

Assembling the cake: 

Slice the cakes to three even layers, brush each layer with the rum orange syrup and set aside, fill a pastry bag with pastry cream & pipe on each layer, Stack the cake layers on top of each other, top with fresh fruits and if you happen to have sour orange jam at home, brush the glaze over the fresh oranges and decorate the sides of the cake with orange slices.

The bitter orange flavor blends so perfectly with the pastry cream and the additional fresh oranges bring all the flavors together in one delicious bite.

Hope you enjoy this cake and share the recipe with your baker friends. Until another week and another recipe, Have fun baking. Love ya