Grease and line your slow cooker pot in readiness, then beat the butter and caster sugar together until light and fluffy, in a large bowl.
175 g unsalted butter, 175 g caster sugar (superfine sugar)
Mix in the lime zest and juice.
Lime zest from one and a half limes, Juice of half a lime
Beat in the eggs one at a time. Beat well after each addition.
3 eggs
Stir in the dessicated coconut.
75 g dessicated coconut
Sift in the flour and baking powder, and fold in.
175 g self-raising flour, 1 tsp baking powder
Transfer the mixture into your lined slow cooker bowl.
Put the lid on, add a tea towel under the lid to catch drips, then cook on high for 1 hour. Then switch to low and cook for a further 40-50 minutes, or until a skewer comes out clean from the centre.
While the cake cooks, prepare your buttercream icing and lime drip icing. For the buttercream, cream the butter with the icing sugar until light and fluffy, then stir through the lime zest.
75 g butter or spread, 150 g icing sugar, Lime zest to taste
For the other lime icing, mix together the lime juice and icing sugar and thin it out if needed with the teaspoon of water, or as much as needed to reach your desired consistency.
100 g icing sugar, Juice of half a lime, 1 tsp water
Once the cake is cooked, trim any burnt edges, slice in half, then fill with the lime buttercream and spoon the other icing over the top and sprinkle with lime zest.