preheat the oven to 180c 350f
Line two rimmed baking trays (jelly roll tins) with baking paper
Add the eggs and sugar in to the bowl of a stand mixer and whip at high speed until pale and the volume has tripled in size and it is full of air. (about 5 to 7 minutes) or use a hand held electric mixer)
Mix the flour, cocoa powder, baking powder and a pinch of salt together then using a sieve add to the egg mixture 1/3 at a time, gently folding it in with a spatula.
Fold in gently so you don't knock all the air out,
pour into the prepared tins and tip them slightly to spread it out, tap them once on the counter to pop any large bubbles then bake for 12 minutes.
While baking place two sheets of baking paper the same size as the cakes on the work top and dust with icing sugar
when cakes are done place them up side down on the the paper then carefully peel off the baking paper, turn the paper you just used the other way around and place on top and roll the cakes up into a tight log and leave to cool completely on a wire cooling wrack.