Preheat oven to 150°C. Generously butter the inside of a 2.4L bundt tin so you ensure the grooves are coated. You can also use 2 x 9inch (20cm) round tins but you will need to adjust the cooking time. If using round tins line the tins with baking paper.
Sift the flour, baking powder, bicarb soda and BakeAid into a large bowl. Repeat so that you have sifted three times.
Melt the chocolate in a bowl over a pan of simmering water, making sure the bottom of the bowl does not touch the water. Once it has melted take it off the water being careful not to burn yourself with the steam Wipe the bottom of the bowl.
Sift in the cacao powder and stir.
Add vanilla extract, sour cream and 80ml of boiling water and stir until it forms a smooth, thick paste.
Place butter and sugar in the bowl of an electric mixer and whisk until pale and fluffy.
Add the eggs one at a time whisking well after each addition.
Stir in the chocolate paste until well combined but do not over-mix.
Fold the flour mix into the batter.
Carefully pour into the bundt tin and smooth the top.
Bake for 45 minutes or until a skewer comes out clean when inserted. If using two round tins start with cooking for 30 minutes and adjust cooking time from there.
Remove from oven and leave in tin to cool for 15 minutes. Turn onto wire rack to cool.
Chop the chocolate and place in a bowl.
Heat the cream in a small saucepan until it just starts to simmer.
Remove from the heat and pour over the chocolate, allow to sit for one minute so the chocolate can start to melt.
Add the Relief and stir until the mixture is smooth.
Pour over the cooled cake.
Serving Size 12