To dream of a cake indicates that you need to learn to share and allocate your workload instead of trying to do everything yourself. Cakes also symbolize selfishness or the feeling of not getting your fair share. More positively, the dream may represent your accomplishments and achievements. Consider also the metaphor a 'piece of cake' or some situation that is easy.
To see a partially-eaten cake in your dream signifies missed and lost opportunities.
To dream that you are buying a cake suggests that you have accepted the rewards and recognition you're getting for your work. You are learning to be comfortable in the spotlight.