black tea bag or loose leaf tea
100ml boiling water
260g plain flour
1 tsp. baking soda
¾ tsp. baking powder
½ tsp. salt
275g granulated sugar
100ml vegetable oil or melted margarine
2 large eggs
1/4 tbsp vanilla extract
2 tsp ground ginger
2 tsp ground cinnamon
1/4 teaspoon cardamom, ground
1/2 nutmeg finely grated
1/2 tsp ground cloves
1/2 tsp instant coffee powder
for the frosting
500g icing sugar
1 teaspoon cocoa powder
40ml strong brewed coffee, completely cooled
1/2 teaspoon instant coffee powder
200g soft butter
Pre-heat oven to 180ºC and line a rectangular 32 x 22 cm cake tin. Place the black tea bag and boiling water into a measuring jug. Set aside to cool.
In a large mixing bowl, combine the flour, cocoa powder, baking soda, baking powder, salt and sugar. Add in all of the spices.
Add the buttermilk, vegetable oil, eggs and vanilla extract into the mixing bowl with the dry ingredients. Whisk, until evenly combined and glossy. Pour in the brewed tea and whisk until smooth. The batter should be quite runny, like a brownie mix. Pour into the prepared baking tin.
Bake for 30-45 minutes or until risen and the middle feels firm but springs back to the touch. The top surface may be cracked. Let the cake rest for 10 minutes in the tin before turning out to cool completely on a rack.
To make the frosting, add the butter into a bowl and beat until smooth and soft. Sieve the dry ingredients into the bowl and continue to gently beat as you gradually pour in the coffee, a little at a time. Add more coffee or icing sugar according to the thickness of the frosting. Let chill in the fridge until ready to use.
When the cake is cool, spread the frosting in thick swirls all over the top. For a slightly marbled effect, reserve about a quarter of the frosting and add in some extra cocoa powder to darken it, before swirling this darker mixture over the frosting on the cake, using a palette knife or small silicone spatula. Cut into squares.