berachos question

The way I understand the basic halachah is that if someone has a food which contains multiple berachos, he makes a berachah on the ikar. However, wheat cannot be tafel so if there is a wheat element to the food, one must make a berachah on that. I think, and correct me if I’m wrong, that this doesn’t mean that the wheat becomes the ikar and everything else becomes tafel, but rather this food has multiple ikkarim. So if the food can be separated, like an ice cream cookie where the ice cream is the ikkar, one should make a mezonos on the cookie and a shehakol on the ice cream. But what if it can’t be separated like a chocolate bar with a cookie center and the chocolate is the ikkar? How do you make both berachos? Do you just make both berchos and then eat it? If so, wouldn’t the second berachah be mafsik between the first berachah and the actual eating?