This question is taking for granted the position of Reb Moshe Feinstein that a food which has two ingredients such as chocolate covered peanuts gets two brachos (blessings) being that both ingredients are desired, they are both an Ikkur (main part of the food) and not tafful(negligible part of the food).
What happens when one ingredient is unknown, such as a bowl of chocolate covered somethings. Are they peanuts in there? Raisins?
Can one now say the unknown ingredient is obviously a tafful being that it is being eaten without any knowledge of what it is?
If the answer to this is yes, it is obviously tafful, what happens before the next bite? Does the proof of intention from his lack of knowledge from the get go continue even after the secret ingredient is discovered?
A related question. If someone has a chocolate covered snack platter in front of them, some compartments containing covered peanuts and some compartments containing raisins, but they are clearly separated.
Does the fact that the person is planning on eating both varieties, or that he grabs without checking which compartment he's grabbing from, prove that the chocolate is the Ikkur to him and the insides are Tafful?