Re adult selfish you are unlikely to work, especially if you used to be in his shadow and move to the lower step of the podium. From time to time turn his attention to himself. For example, next time when he launched into a long story about their own troubles and also start to whine over a broken heel or perhaps unpleasant conversation with colleagues. If he starts to interrupt, just keep talking. Your task is to show that he is along with you, to shift the focus on yourself.
Firmly and without wasting time, explain to the selfish, he behaves disrespectfully towards you. Arguments arguments with concrete examples. If you blame him that he does not say, ask him to remember what you talked about over Breakfast. Lead the conversation in a constructive way, don't attack him with shouts or insults. In any case, don't make a scandal, otherwise he will bring you into your own "blacklist" is not appreciated his fine mental organization.
If he doesn't care about you and literally forces you to constantly stand at the stove and entertain its gastronomic pride, the next time you, say, late at work, warn him that he would come home hungry. Then just calmly ask him to cook you dinner. No need to beg or borrow the attitude of a victim. One "please" would be sufficient. It will help him at least for some time to put myself in your place. Some selfish need to give the right of choice, for example, ask him to prepare a side dish or enjoy a meal delivery service.
The idea that he behaves incorrectly, does not immediately lead to change of behavior. Let the selfish time. Maybe soon he'll review the situation and will give you more attention. Most importantly, don't talk about his narcissism every day. Better take care of their own appearance and learn to manage free time. Think about a healthy love for itself and its own interests, needs, and desires.