Early in the fic, Spike has recently moved in with Xander, and one early saturday morning Xander is watching '30 minute meals' and decides to try and make the meatball subs. So he goes out to the library & gets online for the recipe, then goes home and makes them for he and Spike.
Also in the same fic I think, but maybe not: I think that he ends up getting his own laptop because of Cordelia's nagging.
FOUND - the fic is amejisuto's White Knight, Black Knight. It is a WIP.