The pleasure of a savoury rice-cake stir-fry is the contrast: tender greens, a little sauce and slices with a springy bite. A compact stack of rice cakes dropped straight into the wok can spoil that balance. The outer slices soften while the middle remains a dense block.
Read the storage state first
Rice cakes are sold fresh, refrigerated, frozen and dried. Their preparation instructions can differ substantially. The Woks of Life’s family recipe for stir-fried nian gao distinguishes dried cakes that need soaking from the fresh or frozen slices used in its method. That distinction is more useful than a universal soaking time.
Follow your package and recipe together. If a block needs thawing or soaking before it can separate, do that safely as instructed. For slices that are ready to cook, loosen them gently and drain away excess surface water. Thick cylinders and thin ovals also need different attention at the centre.
Give the cakes a route to heat
Set out the prepared vegetables, sauce and rice cakes before turning on the heat. In the linked recipe, vegetables form a bed beneath the cakes and a covered stage supplies steam. It is a specific cooking method, not a requirement to force every rice-cake dish through the same sequence.
For your own cooking notes, separate three observations: whether the slices have come apart, whether the centre is heated and tender, and whether enough sauce remains to coat the dish. A cake can look glossy while still feeling hard inside. Conversely, prolonged aggressive stirring can damage cakes that have already softened.
Use the quantity of liquid specified by the recipe, then judge the pan before adding more. A tightly fitting lid and a broad open pan behave differently. When adjustments are needed, make them small enough that the dish does not unexpectedly become soup.
Serve a modest test portion first and check its texture once it is cool enough to taste. Aim for a pleasant chew rather than assuming that all resistance means undercooking. Next time, the most useful note will be the brand, shape and storage state of the rice cakes you actually used.