Check out Burrrn, which can burn a CD directly from Flac files. (Actually, what it does is converts the Flacs to WAVs, then burns the CD from the WAVs and then deletes them. But it does it all with no additional work on your part.)
http://www.burrrn.net/?page_id=4In EAC I recommend creating (non-compliant) CUE sheets when you rip your CDs. Then edit the CUE, changing all of the .wav file extensions to .flac. To tuplicate the CD all you then do is double click the CUE sheet file, which will run Burrrn. Makes duplcating CDs from your Flac files very fast and easy.
One thing Burrrn does not do is adjust for CD-RW drive offsets, so if you're a stickler that demands a "perfect" CD duplicate, right down to the sample offset on the disc, then Burrrn isn't the tool to use.