Okay, I don't have many details to go on, but I remember reading this fic on AO3 when I first got into this paring, so it's older (ish... I would guess about two years), and I was basically reading down the top rated fics (sorted by kudos) in the fandom, so it's a more popular fic as well. I don't remember much except for a Tony POV, team stuff, and a confrontation in a conference room post-battle. In the conference room Tony sort of bluffs Steve about their are-we/are-we-not status, not expecting Steve to actually be willing to launch a discussion about their budding relationship in front of the team. Naturally, Steve does. I remember there being kind of a funny bit about Bruce being really uncomfortable being an unwilling 3rd party to such a conversation, but Natasha was into it. I know it's not much to go on, but it's driving me crazy trying to find this. Definitely-probably movie!verse
I think the confrontation might have been about Tony running away after Steve kissed him (or he kissed Steve), and the post-battle debrief was the first opportunity Steve had to talk about it, hence why Tony tried to bluff him out, not expecting he would be willing to have that talk in front of everyone. I remember a line about how Tony thought he should have known better because Steve was the bravest man he knew. Set Post-Avengers, naturally, but before any of the Phase 2 stuff, to further attempt to age it.