The noun 菜 (cài) can mean either "dish" (a prepared food item) or "vegetable," depending on the context. When used in the context of a meal, it typically refers to a cooked dish, as in 我的菜 (my dish).
今天的菜都很好吃。
Jīntiān de cài dōu hěn hǎochī.
All the dishes today are delicious.
这道菜是我妈妈做的。
Zhè dào cài shì wǒ māma zuò de.
This dish was made by my mom.
你想点什么菜?
Nǐ xiǎng diǎn shénme cài?
What dishes would you like to order?