A funny scene that comes to mind in Act II is when Jack and Algy are exposed, making Gwendolen and Cecily realize that none of them are named Ernest, and that they are just not the people who they claim to be.
This scene happens right after Cecily and Gwendolen argue over who is the real fiancee of Ernest. During that previous argument *which is the scene you mention in your question* the women declare war on each other and basically stop speaking.
However, when they both find out that they have been duped, they join forces together once again and enter the house expecting that Jack and Algernon will follow them as if they were damsels in distress.x
Instead of that, Jack and Algernon remain in the garden and....start eating the muffins and drinking the tea that Gwendolen and Cecily forfeit when they fight. So, basically Jack and Algernon have a tea party right after becoming exposed. It is afterwards that they finally decide to go after the ladies to explain themselves.
Even the conversation that takes place between the men is quite funny.
JACK:[Picking up the muffin-dish.] Oh, that is nonsense; you are always talking nonsense.
ALGERNON:Jack, you are at the muffins again! I wish you wouldn't. There are only two left. [Takes them.] I told you I was particularly fond of muffins.
JACK:But I hate tea-cake.
ALGERNON:Why on earth then do you allow tea-cake to be served up for your guests? What ideas you have of hospitality!
JACK:Algernon! I have already told you to go. I don't want you here. Why don't you go?
ALGERNON:I haven't quite finished my tea yet, and there is still one muffin left. [JACK groans, and sinks into a chair. ALGERNON still continues eating.]