One day I was hungry but was feeling too lazy to make a proper lunch, so I just mixed some ingredients I had in the refrigerator with udon noodles and threw it in the microwave....and what do you know, it was really good! I've been hooked on this dish ever since. This recipe was featured in a lazy-cooking cookbook!
You don't have to use frozen udon noodles of course. This recipe is delicious even without the green onions and nori seaweed. I leave them out when I can't be bothered. :) It's also delicious with pasta instead of udon noodles, in which case I think mushrooms and chicken would go well. But really, this tastes the best without a lot of additional ingredients.