Chai-spiced sweet potato cake

Ingredients

• 250 g sweet potato (1-2 medium)
• 120 g mild olive oil, plus extra to grease
• 90 g dark brown soft sugar
• 50 g caster sugar
• 3 medium eggs
• 160 g plain flour
• 50 g ground almonds
• 2 tsp ground cinnamon
• 1 1/2 tsp ground ginger
• 5 cardamom pods, seeds finely ground
• 1/4 tsp ground cloves
• 1 tsp baking powder
• 1/2 tsp bicarbonate of soda
• 1/4 tsp fine salt
• 125 g unsalted butter, softened
• 125 g icing sugar
• 100 g cream cheese
• 30 g salted caramel (optional)

Instructions

1. 1

   Preheat the oven to 220°C, fan 200°C, gas 7. Place the sweet potato on a foil-lined baking tray, then bake for 45 minutes, or until very tender when pierced with a small sharp knife. Leave until cool enough to handle, then cut in half and scoop out the flesh (discard the skins). Mash the flesh with a fork and leave to cool completely – you will need 150g for the cake.

2. 2

   For the cake, preheat the oven to 180°C, fan 160°C, gas 4. Grease a 20cm square cake tin with oil and line the base and sides with baking paper. Put both sugars in a large mixing bowl and beat in the eggs with a balloon whisk until combined. Whisk in the 120g of oil, followed by 150g of the sweet potato mash (some small lumps are fine). Add all the remaining sponge ingredients and stir with a spatula or wooden spoon until smooth. Scrape into the prepared tin, then bake for 28-32 minutes until risen, just firm to the touch and a skewer inserted comes out mostly clean. Leave to cool completely in the tin.

3. 3

   For the cream cheese frosting, beat the butter with an electric mixer until very soft. Sift over the icing sugar and beat until pale and creamy, starting on a low speed. Add the cream cheese and beat again until combined.

4. 4

   Remove the cake from its tin onto a serving board. Spoon on the cream cheese frosting, swirling it to the edges of the cake. Add small spoonfuls of the salted caramel, if using, and drag through a cocktail stick or the tip of a knife to swirl it into the cream cheese. Cut the cake in half, then cut each half into 6 rectangular fingers to serve. Store for up to 5 days in an airtight container.