Prepare bok choy by separating the larger leaves from the stem. Trim the bottom of the stems but leave the small leaves attached to it. Set leaves aside.
Heat oil in a large saute pan on medium-high heat. Add onions and saute for two minutes. Add garlic and saute for a minute. Add bok choy stems, sprinkle with sesame oil and salt to taste. Cover and let it cook down for two more minutes.
Remove the lid and reduce the heat to low. Stir in bok choy leaves and let cook for another minute or two, depending how crunch you like the bok choy.
Gently mix in cashews and serve hot.
Recipe adapted from http://simplyrecipes.com/recipes/baby_bok_choy_with_cashews/, retrieved Feb. 2012.