Mix the sauce ingredients together other than water, and set aside.
Heat the wok over high heat with a tbsp of oil and cook the broccoli and onion and stir fry, tossing occasionally until the vegetables have black spots and are crisp/tender. Set aside.
Add another tbsp of oil to the wok and add the chicken. Cook, stirring occasionally, until it is nicely browned and cooked nearly through. Add the ginger, garlic and the rice cakes, along with the sauce and a little water. Reduce heat to medium low and simmer, tossing now and then, to let the rice cakes cook.
The rice cakes take about 5-7 minutes to cook from frozen, so add a little more water as needed if the pan is getting dry and keep stirring them. Taste one now and then, to check doneness. They should be soft, not hard, but still chewy.
Add in the spinach and the onion/broccoli as well as the scallions and toss it all together, simmering until the sauce is thick. The rice cakes will thicken the sauce. Serve with chili crisp and extra soy sauce.