XO is very good but usually quite hot, at least to my taste. I have to use it in small amounts or it blows away my family with heat.
There should be lower heat grades out there, but all the asian stores in my area only stock the extra hot. It's often behind the counter with the abalone as its somewhat expensive and a prime shoplifting target. I should make my own lower heat version myself one of these days. Eileen Yin Fei Lo offers a recipe in her book Mastering the Art of Chinese Cooking though there are other recipes out there too. BDL often makes a dry rub out of just the dry ingredients.
Fantastic guess! Wu kok is in the dim-sum ball park, but cakes aren't kok. They're called wu tul gow.
There are a lot of variants of XO. I keep the cost down on mine by buying broken pieces of dried scallops and stretching them with dried shrimps.
My three favorite versions all start with very finely or micro-brunoise of dried scallops; dried shrimp; hot red chilis; hot green chilis; and garlic chives.
HK traditional Dry: Mix and there you go. My favorite, very versatile.
HK traditional Liquid/Paste (as beloved by Japanese and westerners): Mince a little onion, red bell pepper and garlic. If you like you can mince a little bit of cured ham as well. Pass fry the pepper in a little oil until it starts to soften, then add the onion. Pass a few times, and add the remaining ingredients except for the chives. Pass some more, and when the garlic is fragrant, add a little brown bean sauce in a volume about half of the other ingredients combined. Cook only until the sauce is heated through and stir in the chives. Turn out and use when and as necessary. Sauce should be very chunky but of an oily consistency similar to the "chili oil" you see on restaurant tables. Yes, it's great, but... a lot of trouble, and the complications of extra ingredients and create what's essentially a luxury version of brown bean sauce. Blunted impact compared to the simple, dry version.
Mignonette: Micro brunoise some shallot, enough so that it's roughly 1/3 of the total of dry ingredients, mix with the other ingredients, add just enough Chinese red vinegar, Japanese white rice vinegar, or lemon juice to "float" the other ingredients. Consistency should be chunks of stuff in a liquid, not wet chunks of stuff. Fantastic with fish of all sorts, especially raw. My own twist, if you hadn't guessed.
It might be interesting to do a cooked, liquid/paste, substitute canned chipotle and some of the adobo for the fresh chilis and brown bean sauce. Lightened and brightened with a squeeze of lime, it would do very well with simple grilled or sauteed fish I think.