I thought I had this fic bookmarked, but I don't, and I couldn't find it through Google and trawling through my favorite authors' CM fic listings.
It's an AU where Rossi wasn't joking when he said Reid was left in a basket on the steps of the FBI, and he is Reid's adopted father. The pairing was Hotch/Reid, Prentiss/Rossi, iirc. Please help.
ETA: Found by
jujuberry136 kyrdwyn 's
Blaze with Glory series.