The Glutenfree Alchemist - aka Kate - posted the recipe for this here.
It looked so good I just had to try it. I didn't buy enough mascapone (250g instead of 300g) so used what I had and used 50g less icing sugar, there was plenty. I normally hate making rolled bakes of any kind as they can be difficult and very nearly didn't even try but I did and herewith some photographs. Ready for the oven:
The texture is beautiful but we would reduce the sugar a little next time, in both the sponge and mascapone elements, maybe 10g or so less as we are not too keen on too sweet a dessert.
Ab fab darling!