This is not a traditional Japanese recipe, although it makes use of various
traditional Japanese ingredients. Nor, despite allusions from the title to the
contrary, is it a traditional Italian recipe. Rather, it is a confusion of
cultures, a melding of mores, a pan-hemispheric hybrid of piquancy. And, more
importantly, it is rather delicious.
You will need the following to make enough sauce for a decent marinade for
two:
Mix all the ingredients together and put them in a non-stick pan (or a
sticky pan, if someone else will be tidying up the mess) over a low heat. Stir
softly. After a while the sauce will start to thicken. When it does, give it a
few more minutes and then remove it from the heat — you're aiming for an
easily pourable sauce of single-cream consistency, not a thick French gravy.
So now you have your sauce. A good start, but not yet cause for a pantheon
of resplendent angels singing the Hallelujah chorus. At best you're in busker
territory here, and not a very good busker at that. This is, after all, only a
sauce.
The most obvious continuation is a marinade of pork or chicken with chopped
onions. Chop your meat of choice, mix in the sauce and onions, cover and leave
it in the fridge overnight. It can then be stir-fried with an assortment of
vegetables (carrots and peppers work well) and served with rice.
The sauce can also be used when grilling strips of meat. It may help to make
a slightly thicker sauce (use more arrowroot and cook for a bit longer)
here.
Finally, the sauce can be bottled and kept in the fridge for a while and
poured onto noodles — it can turn a five minute student meal into
something that almost resembles proper food.