Michelle Darmody: How to bake spiced sweet potato cake
Michelle Darmody shares her spiced sweet potato cake recipe
Sweet potatoes are remarkably good value at this time of year. They are a good baking ingredient as they are sweet and soft and add texture as well as fibre to your cakes. I find it handy to bake them in their skins then scoop the inside out and add it to cake and biscuit batters.
Spiced Sweet Potato Cake
I have fond memories of living on roasted sweet potatoes in college. We thought we were fancy, cutting a slit in the still warm skin and adding a spoon of garlic butter. It was a sign we were having friends to dinner if we added coriander and chopped chil
Servings
10Preparation Time
25 minsCooking Time
55 minsTotal Time
1 hours 20 minsCourse
MainIngredients
220g butter, soft
300g golden caster sugar
2 tsp vanilla extract
3 eggs, lightly beaten
1 tsp powdered cinnamon
1 tsp mixed cake spice
1 tsp powdered ginger
300g self-raising flour
2 tsp bread soda
600g roasted and mashed
sweet potatoes (about 4 small to medium)
240ml buttermilk
For the icing
120g icing sugar
15 ml orange juice
Zest of 1 orange
¼ tsp ground cinnamon
Method
Line a 9-inch round cake tin.
Preheat your oven to 180ºC/gas mark 4.
Beat the butter and sugar until light and fluffy and pale in colour.
Lightly beat the eggs with the vanilla and slowly add them to the butter mixture until combined.
Add in the mashed sweet potato and combine with a wooden spoon.
Sieve the spices with the flour and bread soda and add these to the mixture to form a batter.
Add in the buttermilk and combine.
Scoop the batter into the tin.
Place the tins into your oven and bake for 55 minutes until a skewer comes out clean.
Allow to cool in the tin until cool enough to handle, then place onto a wire rack to cool completely.
To make the icing, whisk the icing sugar, juice, cinnamon and zest until smooth.
Top the cake with the icing.
I use a spring-form or loose-based cake tin for this recipe. To line the tin, cut a circle three inches bigger than the base of the tin. Fold the circle in half, fold it in half again, and keep folding until you form a long, narrow triangle. Place the pointy tip of the triangle at the centre of the base of your cake tin. Cut a slit in the outer edges of the triangle so there is a slit from the outer edge to the edge of the base. When you open up your circle the centre will fit on to the base and the cut pieces will fold three inches up the sides.
Baking the sweet potatoes in their skins, instead of boiling or steaming them, helps to concentrate their natural sweetness and prevent them acquiring excess liquid.
The acid in the buttermilk reacts with the alkaline bread soda. This reaction creates carbon dioxide bubbles, helping the cake to rise. If you find your cake is flat it may be that the bread soda is out of date. Bread soda loses its leavening power after about six months. Because you use so little of it in most recipes it can tend to go off, even in the cupboard of the most avid bakers.
The spices are predominant in this recipe, adding a warm, sweet back note. Adding the mixed cake spice, as well as the cinnamon and ginger, allows the addition of a small amount of many other spices into the mixture.
Ensure to scrape down the bowl a few times when you are mixing the eggs into the butter and sugar mixture. It is easy to forget to do this, leaving a layer at the edges of the bowl that is not fully incorporated with the rest of the cake’s ingredients. Having uneven distribution can lead to a heavy and dense cake.
It is important to make sure the sweet potato has cooled down before adding it to the batter, otherwise it will melt the butter and make the cake greasy.
Place the cake back into your oven for five-minute intervals if the skewer does not come out clean on the first test.
The cake will last three days in an airtight container. If you want to freeze it I would do so before adding the icing.
