FOUND: Tony/Bucky
Looking for a post Winter Soldier fic where Bucky breaks into the tower for a reason I can't remember. I think he might of been trying to find Tony for help with his arm? Anyway, he gets in and befriends the staff and Tony. I think the female staff he befriends was an OC based on the author, along with two other female OCs. I remember one of the OCs delivers donuts while he is there and he protects the donuts from Clint who tries to steal the donuts from the vents. No one seems to realize he isn't supposed to be there and that he is Bucky Barnes. Once Tony realizes who he is I think I remember him hiding Bucky in tower on his personal levels, so that Bucky can avoid Steve. It ends in a Bucky/Tony pairing.
2/16/23 FOUND: It is Adorato by wakandan_wardog