Hi, first attempt at a Yule log today (rehearsal) using Mary Berry recipe. Baked for 9 minutes at 180c and it was springy but not firm to touch when I took it out of oven. Immediately inverted on to clean greaseproofvsnd removed bottom grease proof. Edges looked a bit ‘soft’ rolled up and left to cool. Unrolled when cooled to fill and it was completely stuck to the paper. Cracked into stripes when tried to roll when filled. Was my cake under cooked? Should I have sprinkled caster sugar on the paper before inverted? Any fail safe swiss/chocolate roll recipes?