Melt the white chocolate and butter together in the microwave. In my 1000 watt microwave this took 90 seconds. Stir until smooth, then stir in the lemon zest.
200 g white chocolate, 225 g butter, zest of 1 lemon
In another bowl, whisk the sugar and eggs together.
225 g caster sugar (superfine sugar), 3 medium eggs
Add the melted chocolate mixture into the egg and sugar mixture, and whisk again.
Fold in the flour until just combined. Don't overmix.
225 g self raising flour
Grease and line your slow cooker bowl. This was made in my 3.5 l slow cooker.
Pour the cake batter into the lined bowl.
Cook on high for 2-3 hours, or until a skewer or toothpick inserted in the centre comes out clean.
Note: all slow cookers are different, yours may take less time (or longer!), look out for burning and remove as soon as the centre is firm and the skewer or toothpick comes out clean.
Allow to cool.
To make the icing, whisk the crème fraîche with the icing sugar for 3-5 minutes, until soft peaks form. Stir in the lemon juice.
300 ml light crème fraîche, 70 g icing sugar, 1 tsp juice from the lemon
Spoon the icing on top of the cake and top with blueberries.
Blueberries to top
Keep the cake chilled. Best consumed on the day it is made.