I thought this was a lovely way of cooking sea bass. The fish released a lot of fragrant steam when I opened the paper and the flavours were subtle and delicious. However, I reduced the rosemary as the rosemary we get here in Greece is much more pungent than the one typically found elsewhere, and I didn't want to overpower the fish. I was also surprised by how much flavour was added by such a small amount of butter. A great recipe.