Start this recipe the night before you plan to make it.
Mix 300g sultanas, 200g roasted or stewed rhubarb and 100g brown sugar together in a large bowl. Cover with 300ml strong hot tea and leave to soak overnight.
Pre-heat the oven to 150°C(fan)/170°C/gas mark 3. If using a flax egg mix 1 tbsp ground flax seeds with 2.5 tbsp water and set aside to thicken.
Grease and line a 2lb/900g loaf tin with baking paper. Stir 275g self raising flour and the flax egg (or beaten egg) into the fruit mixture. Pour into the prepared tin.
Bake in the oven for 1 1/2 to 1 3/4 hours until a skewer inserted in the centre comes out clean. Cover the top with foil if it's getting too brown.
Allow to cool in the tin for five minutes then carefully turn out onto a cooling rack.
If you're icing the cake let it cool completely before doing so.
Sift the icing sugar into a bowl and gradually stir through the cold water, a little at a time, until you have a thick, smooth icing.
Drizzle over the cake and allow to set for a few minutes before serving.
NB: to roast the rhubarb chop into 2cm pieces, toss with 20g caster sugar (or more if you prefer it to be sweeter - I don't think it needs more sugar in this recipe), cover and roast for 20-30 minutes, stirring occasionally, in an oven preheated to 200°C.