Preheat the oven to 180°C and line a 23cm baking tin with baking paper and grease the sides.

Using a mixer, with the paddle attachment, place the self-raising flour, baking powder, orange juice, butter, demerara sugar, eggs and orange zest in the bowl and beat until all well combined. Fold the chocolate in. Pour the mixture into the prepared baking tin.

Place in the preheated oven and cook for about 30 minutes or insert a cake tester and when it come out clean remove the cake from the oven and place the tin on a cooling rack and allow to cool in the tin for about 10 minutes.

For The SYRUP: In a small pan on a low heat, place the orange juice and sugar and mix until the well combined. Once the sugar has dissolved, simmer on a low heat until the syrup has slightly thickened and then remove from the heat.

While the cake is still in the tin, use a skewer to poke holes all over the cake. Brush the cake with the orange syrup and allow it to sink in. After 5 - 10 minutes remove from the tin and place on a wire rack to cool.

Dust with icing sugar and serve.