I've been following Harumi's Bok Choy recipe (with a few modifications) and not really getting anywhere. The first time, it was edible. The second time, the stems came out good and the leaves came out passable. The third time, the leaves came out good and the stems came out possible. And everything kept coming out too oily.
But today, finally, I made something that came out pretty dang tasty. The trick was to ensure I had a really high heat -- which requires a lot of patience on an electric cooktop. I used 2 tbsp of corn oil and waited until it was really "smoking" (or evaporating rapidly in a very visible way).
It wasn't without incident as I burned the garlic nearly immediately. So, I'm thinking I either need thicker pieces of garlic (the recipe calls for finely chopped) or I need to add the stems of the bok choy at the same time as the garlic (which may cool the oil down enough to not burn it). I'm sure though that the idea is to get the garlic flavor in the oil before cooking anything, but I can't imagine that not happening from the initial temperature drop. Or maybe I just need to be faster (aka. throw garlic in, grab the stems, wait half a second, throw those in).
Even with burned garlic (which I had to fish out / eat around), it was vastly improved by high heat and then adding seasame oil and soy sauce with it off the heat.