It was my friends’ homemade corned beef that made my husband – a vegetarian for years – eat meat again. That brined brisket was so tender, so succulent, that he broke down and had a taste. Then he had a plate of it. Clearly, this was something I needed to be able to make myself.

So I did, and homemade corned beef is now a St. Pat’s tradition in my family. (Corning beef at home is not difficult; recipes abound on the Internet – you can find mine at – and I encourage you to find one and do it yourself, although you should be aware that it takes five to seven days.) But inevitably, I end up with leftover corned beef, and after a nice hash with a poached egg for breakfast and maybe a sandwich with some spicy mustard for lunch, I find myself a bit flummoxed as to what to do with the rest. Taking a cue from Thanksgiving, when I use the leftover turkey to make soup, I wondered if I could do the same with leftover corned beef. Why not?

I’m a sucker for French onion soup because it’s the best of all things: a rich, salty yet slightly sweet broth, tons of melty cheese and bread. Why not mix things up a bit and put the classic flavors of a Reuben sandwich into a soup? I started with the broth; I wanted it to be beefy, but a straight beef stock can overpower other flavors, and I wanted the flavor of the corned beef to shine through. I tried adding a bit of beer to the broth, but it made it too bitter. After experimenting with chicken, veal and beef stocks in varying combinations, I found the best to be veal stock cut with chicken stock: The chicken stock lightened the broth, and the veal stock lent richness without being too salty.

Once the first layer was established, it was time to start bringing in the flavors of the Reuben. Caraway seeds were an obvious choice: Commonly used in rye bread, the caraway seed has a light anise flavor that almost immediately made the soup taste “Reuben-y.” Celery seed – an addition that resulted from staring at my spice rack while thinking about eating a Reuben, which made me think of delis, which made me think about Dr. Brown’s soda, leading, obviously, to Dr. Brown’s Cel-Ray soda and then to celery seed. Makes all the sense in the world, right? – added a nice earthy, herbal note. Of course, the toasted rye “croutons” and Swiss cheese melted on top of the soup are my favorite parts, essential elements of the sandwich but also clearly a tip of the beret to the French onion soup j’adore.

A toasty Reuben is a wonderful thing, but a bowl of Reuben will cure what ails you after you’ve been Irish all day. Here’s hoping you have leftover corned beef on March 18. Sláinte!