A couple of weeks ago we went to Mitsuwa, where I spotted some 2-liter cartons(!) of cheap sake. And they were on sale! So I bought one! Then I realized that I didn't necessarily want to swig half a gallon of sake anytime soon and decided to cook with it.
Here's what I made:
1/2 cup cheap sake
1/2 cup mirin
1/4 cup rice vinegar
1/2 cup red miso paste
3-4 cloves of garlic, minced or microplaned
1 tablespoon (or so) of minced or microplaned fresh ginger
1 teaspoon sesame oil
Mix it all up in a bowl. There's your marinade. We've used it on little cubes of tofu and on tempeh. Drop your stuff in, mix it up good, and let it sit for half an hour or longer. Here it is:

I then retrieve the proteiny stuff and fry it in a little peanut oil (or something high-temperature) until it browns (tofu) or gets crispy (tempeh).
I've been making it with veggies and greens and stuff. The first time it was brussels sprouts, which I added along with the rest of the marinade and stir-fried until they were hot and yummy, and served over udon noodles:

When a friend from the East Coast and her fellow visited earlier this week, we threw in, let's see... We didn't have rice vinegar, so I put in the juice of two limes instead along with a bit of lemon grass, and cooked it up with some carrots, bok choy, and Thai basil, and served it over brown rice. It was DELICIOUS.

And now I'm out of sake and miso, but I'll be back in San Jose in a week or two and I can pick up some more then. I think this is destined to become a staple... It's quick and easy and seriously tasty.