Preheat the oven to 200 oC
Beat together the caster sugar and eggs until light and fluffy

Stir in the gluten free flour, cocoa powder and water
Pour into a shallow swiss roll tin about 13″ long

Bake in the centre of the oven for 10-12 minutes
Remove from the oven and trim about 1 cm off all the edges

Place on a piece of baking paper and roll up
Leave to cool

Beat together the icing sugar, cocoa powder and dairy free spread until light and creamy
Unwrap the cake and spread half on the chocolate buttercream

Roll up the cake and top with the the rest of the buttercream