Preheat the oven to 180°c.Grease a Swiss roll pan or oven tray and line it with parchment or wax  paper, grease the top of paper as well to prevent the cake from sticking. In a bowl add eggs and sugar and beat till foamy. Add oil, tsp vanilla essence and mix through, sift in the dry ingredients, coffee and mix till smooth.Pour the batter into the prepared baking tray and spread evenly.Bake for 10/15mins till done, use a toothpick to test if the center is done

Place wax or parchment paper on a flat surface and sprinkle cocoa powder all over. Turn the cake over onto the prepared paper and peel off the paper it was baked with carefully,using a long knife to hold the cake down while you peel it off to prevent the cake from breaking.Roll the cake while hot with the paper inside and leave it to cool completely. Prep the buttercream,unroll the cake and spread the buttercream evenly, roll the cake up again without the paper and leave to set for an hour.