Also, at some point in this story Tony (in his suit) is thrown through a wall and a building collapses on him. He's about to bleed out, but Loki heals him enough for rescue to come (though I think he leaves before the Avengers get to Tony). This is the scene that really stands out in my mind.
Does any of this sound familiar? I've been searching AO3 for days and it's starting to drive me a bit nuts.
ETA: I've just verified that it's not Tricks of the Trade. However, the mention of Loki feeding Tony Asgard apples is striking a chord -- I think it's this fic where Loki keeps tricking Tony into eating Golden Apples (apple pie, apple pancakes, etc.) Eventually Tony figures out that these aren't just regular apples that Loki's feeding him.
ETA2: So it turns out the apples were in an entirely different story (and if anyone remembers that one, I'd love to read it again -- if it helps, I think one of the dishes was apple fritters). The original story was found by the awesome hikari910 and is Debt by Storynerd, found here.