One of the things I brought back from Kyoto (specifically Gekkeikan's museum shop) was lots of this stuff.
When the sake rice has finished fermenting, the 'mash' is filtered with big cloth screens. Two things are produced: the filtered sake, and the pressed rice solids – this is sake kasu.
|You can even see the imprint of the filter cloth here.|
There are lots of different ways to make kasuzuke paste: mirin no sugar, mirin with brown sugar, with miso, without miso, soya sauce or rock salt... this is just the recipe I arrived at after sneaking a few tastes as I went along.
I also added a dash of ginjo sake. Not just any ginjo sake though: Gekkeikan ginjo sake from a retro-style bottle that can only be purchased at Gekkeikan Okura Museum. This bottle is styled after one of the first glass bottles produced in the company's very long history. The sake in it is long gone, but I'll keep the bottle forever (it's currently displayed on a shelf in my kitchen).
I had a blast using my new veggie cutters to make carrot and daikon flowers. I kept the daikon raw and lightly boiled the carrots. As for the renkon (lotus root) slices, I simmered them for 20 minutes in a broth made out of 1 part mirin, 1 part soy sauce and 4 parts water. Simple but delicious.
Alright, enough of me talking. Ready? Let's make salmon kasuzuke!
4 salmon fillets
100g sake kasu
5 tbsp mirin
2 tbsp sake
2 tbsp caster sugar
1 tbsp sweet white miso paste
1 tbsp soy sauce (light)
1) Break up the sake kasu into small pieces, and in a small pan over a low heat, melt and stir it into a paste with the mirin, sugar, miso paste and soy sauce. Turn the heat off, let cool and little and stir in the sake.
2) If it's still lumpy (mine was because I'd been storing the sake kasu in the fridge and it was solid), use a hand bender to smooth it out.
3) Coat the salmon fillets in a generous layer of the mixture, cover in clingfilm and marinade in the fridge for 2–7 days.
4) Generously brush sesame oil over a griddle pan, heat the pan on high until smoking, and turn the heat down to low. Pan fry your fish for about five minutes on each side, depending on how thick they are (you can see how cooked through they are by peeking at the sides).
5) Serve with steamed sweet short grain rice (the sticky kind), your chosen veggies and a sprinkling of chopped spring onion.
That's it! The hardest part is waiting for a few days. Patience pays off though: at the end of the wait is a perfectly-caramelised, fragrant piece of fish. I'm glad I bought so much sake kasu now, it's impossible to find it in the UK. Although I did hear the UK's first sake brewery opened last year... I may actually get into contact with them to see if I can steal/buy theirs. Worth asking, right? If not... I'll just have to return to Kyoto sooner rather than later.