A kosher martini is often made with vodka and olive juice and a whole olive is added to the bottom of the glass. The olive adds flavor to the drink, and it also soaks up some of the alcohol, and is typically eaten after finishing the drink. Do we make a Bracha on the olive? Would the same apply if using pickled pearl onions (also common)?
What you are asking is a bit controversial, but it would seem that you would make a bracha on the olive. The reason is (according to what you are describing) because the olive is not there for itself, rather it is only there to give taste to the drink, and indeed the taste of the olive is a tafel to the drink. However the olive itself, since it is not there to enhance the drink it isn’t a tafel. This is different than a carrot on a piece of fish, because the whole carrot is there to decorate, therefore even if it eaten after the fish it is a tafel and doesn’t have its own bracha. However in your case, the olive is not there for itself, rather only for its taste.