Add the rest of the cake mixture on top and swirl slightly.
Cook for 1-2 hrs on high (see notes above) or until a skewer comes out clean.
Remove from the pot when it has cooled enough to handle, and allow it to cool fully on a rack. This will take quite a while.
Once it is completely cool you can ice it if you want to (or just eat it up!). I topped mine with blueberry buttercream made with 150 g butter, softened, and approx. 300 g icing sugar, whizzed up using the electric whisk. I microwaved a handful of blueberries in a little water for a minute on high, then left it to cool and removed the skins. Then I stirred the juice into the buttercream little by little to achieve the desired colour.
300 g icing sugar, 150 g unsalted butter, a handful of blueberries