You can now get you filling ready. Combine the melted chocolate, cocoa, flour, soft butter, sugar and coffee into a paste.
The following morning, take the dough out of the fridge and punch the air out of it. Feels counter intuitive, but it's necessary. The dough should be much firmer now, as the butter will have set overnight.
On a lightly floured surface, roll your dough out into a rectangle roughly 30 x 40cm. It does not need to be exact.
Generously spread the chocolate coffee butter mixture over the whole surface of the dough. This is why it's important to to have soft butter.
From the long edge, carefully roll the dough up swiss-roll style.
Cut the dough into 12, roughly 3cm slices. I like to use unflavoured dental floss to do this. Wrap the floss around the roll and pull tight until it slices through the roll. If you'd like larger rolls, then cut into 8.
Arrange cut side up in a lined 9 x 13in tray. I line mine with greaseproof paper so the rolls are easier to take out later.
Leave to rise for 30 minutes at room temperature. Preheat the oven 170°C. Pour the cream over the risen rolls and gently spread. Use all the cream.
Bake for 20-25 minutes until golden brown. Leave cool in the tray.