What should you do with cake leftover, but made by the restaurant for your special occasion?

Four of us went away for my birthday to a lodge. My husband asked them to make a "torte" for me (unbeknownst to me). They made a flourless chocolate cake for me and served it whole after dinner. I served us each a piece but there was quite a bit left over. What should you do with it? Take it home or give the remaining to the servers? I can't believe he asked for that, first of all, nor did he offer to pay for this special request. I really don't feel it is their obligation to make a cake. But they did!