Encore Bistro in Larchmont (http://www.encore-bistro.com/dinnerme...) has it, but I've not tried it. Bistro Parisien in Eastchester doesn't appear to have a website, but they may have it ((914) 337-8447).
I had a good cassoulet at Bistro Rollin in Pelham. I enjoy cassoulet but don't order it often so take the rec for what it's worth but I believe its worth a try. If you do, please post. I'm interested to hear your opinion.