I see some people are saying that she should've asked to change the utensils. It might seem more logical, but the thing is is that she wants to teach the maid a lesson.
Sure, she could've asked, but the maid could've lied and apologised saying she "messed up" while making it seem like Penelope is making a big fuss over it. The maid would still give her shitty food and nothing would change. The fact also stands that this maid has been doing this for a long time, just like how Emily has been stabbing her with a needle.
Penelope wants to strike fear into the maid just like she did with Emily by basically saying through her actions, "If you keep this up, I'm going to put you through something even worse than hell.", and thus she does this by making the utensils fall. She wants to embarrass the maid and make sure she won't test her again.