Curry udon is one of the most popular ways to use up leftover Japanese curry sauce. It is certainly my favorite, and I look forward to eating curry udon every time I make Curry and Rice. It is almost like the joy of eating a turkey sandwich on the day after Thanksgiving here in America. Some things just taste better the next day!
You may find it interesting to know that we use Dashi (fish broth) to thin the leftover curry sauce which is almost like thick gravy and usually with meat. The meaty and lumpy sauce that resembles the western style stew is mixed with some delicate dashi broth. Really? Yes, and believe me, it works. Since the sauce is watered down a bit with dashi broth, we usually add some sort of starch (using corn starch here) to thicken, and a bit of soy sauce can be added for flavor.