The recipe provided makes a 9inch triple layered cake which I thought was too much for just me and a flatmate and so I halved the recipe and baked it in a swiss roll tin instead. I then cut the cake into three equal sections, sandwiched it together with the orange filling and covered it with the chocolate frosting to create a triple layer oblong cake.
I loved the texture of the sponge. It is very light, springy and studded with tiny air holes. It also has a slight chewiness to it (in the good way), whether this was down to the sweet potato or whisking the egg whites separately to the yolks I’m not sure, but whatever the cause it produced a delicious cake. It was pale golden in colour and lightly speckled with streaks of orange, hints at its secret ingredient. Incidentally, the recipe says to roast the sweet potato for an hour in the oven to make it soft but I was pushed for time and found a quick blast in the microwave to be just as effective.
The cake also used as assortment of spices, cinnamon, nutmeg and cloves which complemented the cake perfectly. Other bakers have described it as tasting similar to carrot cake and I totally agree. It’s got the same earthy spiciness, only without the fruits and nuts. I think chopped pecans would be a fantastic addition though. I was a little worried how sweet potato, chocolate, orange and spices would all taste together but I am pleased to say they really do work. It’s the perfect cake for autumn.
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Sweet Potato Cake with Orange & Chocolate Frosting
(Recipe from Shy High Irresistible Triple Layer Cakes by Alisa Huntsman & Peter Wynne) Makes a 9-inch triple layer cake
2 medium or 1 large sweet potato (pumpkin or butternut squash)
360g cake flour*
3 tsp baking powder
1½ tsp cinnamon
¾ tsp nutmeg
¼ tsp cloves
5 eggs, separated
450g and a separate 55g caster sugar
1½ tsp vanilla
(*The recipe calls for American cake flour and if you only have plain flour on hand, you can use 300g plain flour plus 60g cornflour)
Preheat the oven to 200C.
Prick the sweet potatoes in 2-3 places, place on a small baking dish and bake for 1 hour or until the potatoes are very soft. Remove from the oven and cool slightly.Reduce the oven temperature to 180C.
Butter the bottoms and the sides of the pans and line with parchment paper. Butter the parchment paper also.
When the sweet potatoes are cool peel off the skin and remove any dark spots. Cut the potatoes into chunks and puree in a food processors. Puree until smooth. Measure out one cup (210g) of potato puree and set aside.
Sift the flour, baking powder, cinnamon, nutmeg, and ground cloves. Set aside.In the bowl of electric mixer add the egg whites and attach whip attachment. Beat on medium speed until egg whites are frothy. Raise the speed to high and gradually beat in the 55g of sugar. Continue to beat until the egg whites are moderately stiff.
In another large bowl with the paddle attachment, combine the sweet potato, butter, vanilla, and remaining 450g sugar. Beat until light and fluffy. Add the egg yolks one at a time. Make sure to scrape the sides of the bowl after each egg yolk is added. With the mixer on low speed, add the dry ingredients and milk in alternately in 2-3 additions. making sure to begin and end with the dry ingredients.
With a large spatula, fold in one fourth of the egg whites into the batter to lighten. Then fold in the remaining egg whites until no streaks remain. Making sure to not over mix or this will deflate the batter.
Divide the batter among of the three pans.Bake for 25-30 minutes or until a cake tester comes out clean. Let the cake layers cool in the pan for 10 minutes. Then turn out the cake layers onto a wire rack and cool completely at least 1 hour.
To assemble the cake, place one layer flat side up on to a cake stand. With a pastry bag fitted with a 1/2 inch round tip and filled with chocolate cream cheese icing, pipe border around the edge of the cake.
Fill the center with the orange cream filling smoothing it to the edge of the border. Place the second layer on top and repeat the process. Place the third layer on top and use all the chocolate cream cheese frosting to cover the top and sides of the cake.
Chocolate Cream Frosting280g cream cheese at room temperature
100g butter at room temperature
450g sifted icing sugar
40g dark chocolate melted and slightly cooled
In a large mixing bowl, beat together the cream cheese and butter until fluffy. Slowly add the powdered sugar to cream cheese butter mixture. Making sure to scrape down the sides the sides of the bowl. Then beat until light fluffy 2-3 minutes.Measure out one-third of frosting and set aside.Add the melted chocolate to the remaining icing in the bowl and beat until well combined.
Orange Cream Filling
The reserved cream cheese icing from above
2 tablespoons of frozen orange juice concentrate, thawed (or grated zest of one orange)
¼ tsp orange extract
Stir together all the ingredients until well mixed.