Grease and line a 23x33cm swiss roll tin.

Sift together dry ingredients and set aside.

Beat eggs in a small bowl until thick and pale.

Add brown sugar in 4 lots, beating in-between until dissolved.

Add molasses and mix well.

Fold the wet mixture into the dry mixture.

Pour into prepared tin and bake for 12 minutes at 180oC.

While the cake is cooking, place a sheet of baking paper on a tea towel on the bench.

Sprinkle caster sugar over the baking paper.

When cooked, the edges of the cake will have slightly shrunken away from the edge of the pan.

Immediately turn the cake out onto the sugared baking paper.

Very carefully remove the baking paper that lined the tin.

Roll the cake up from a long edge with the sugared baking paper and tea towel.

Leave the cake rolled up to cool.

When cool, carefully unroll and remove the tea towel and baking paper. Don't stress too much if there is a crack or two, as the buttercream will help to hold it together.

Spread 1/3 of the buttercream over the cake and roll it back up.

Spread the remainder of the buttercream over the rolled cake, and decorate as desired.