What you want to ask is, is it correct to cook green mung bean soup with a lid or an iron pan? It is correct to cover the pot and cook.

Because polyphenols are easy to oxidize, cover the pot when cooking mung bean soup to reduce the chance of mung bean soup contacting the air. In addition, it is best to cook mung bean soup with pure water, or add some white vinegar to tap water to avoid discoloration of mung bean soup after a long time.