If I have a bagel and want to eat it with cream cheese, should I first make the bracha on it while the bagel is whole and then eat a bite and then cut it and spread the cream cheese, or should I slice the bagel and spread the cream cheese and then make the bracha? I dont really have any desire to eat the bagel without the cream cheese, so which is better more important in halacha my desire in how to eat the bagel or having a whole bagel?
It is best to recite the blessing while the bagel is whole.
The best advice would be to make the berachah on the whole bagel, and dip the bagel in the cheese before eating it. This way, you both eat it whole, and eat it with the cheese. Alternatively, begin to cut the bagel before reciting the blessing, and complete cutting it after the blessing, inserting some cheese as you eat it.
Sources: Orach Chaim, 167:1. In general, the virtue of a whole food takes precedence over the virtue of a food that one prefers, at least when the two have the same blessing (Orach Chaim 211). This would certainly be the case when the very same food is being discussed.