Question:
"After one started eating crackers, he decided to spread some cream cheese on it – a beracha is now required. Even though normally it would be included in the mezonos said on the cracker, here it cannot, since when making that beracha he did not know he was going to eat it, and it was not in front of him [unless he normally eats it together]."
What is the source that if it is in front of him it counts as a taful even though he didnt have it in mind and he started eating without it?
Answer:
The idea is that when a person says a bracha, one usually has in mind to eat from what is in front if him, and is therefore considered a tafel to the crackers. See O:CH 177-4 and M:B 18.
