Prepare your swiss roll tin by greasing it and then placing baking paper onto it. Make sure it fits really well as you want the full shape of the tin.
Preheat your oven to 180C Fan / 200C.
Using an electric hand whisk, whisk together your sugar, eggs and orange extract until light and a little frothy. It should only take a few minutes.
Sift in your gluten free flour, xanthan gum and cocoa powder (always sift cocoa powder otherwise it can be quite lumpy). Fold this into your mixture carefully until fully combined.
Pour/spoon the mixture into your tin, ensuring it spreads right to the edges. Try your best to get it even as it will be pretty thin.
Bake in the oven for about 9 minutes. The sponge should have come away a little bit from the sides of the tin and be slightly risen.
Remove the sponge from the oven and very carefully invert it (turn it upside down!) onto another piece of baking paper on a flat surface. Carefully peel off the baking paper that was on the bottom of it in the oven.
Whilst the sponge is still warm, roll the sponge up with the paper inside it as you roll. Put your rolled up sponge to one side and leave it to cool completely whilst still rolled. I usually put something heavy against it to ensure it stays fairly tight and doesn't unroll.