느냐면

As for what it was —

It sets up an answer to a question the speaker has just posed themselves, and the answer always follows: so here is how we did it; what was good about it was; who the perfect fan refers to is. It is a way of holding the listener's attention across the pause before the payoff. In relaxed speech you will also hear it as 냐면 and, with an extra syllable, 느냐면은.

Register: conversational; explaining and storytelling