Penelope could've easily continued arguing with him, but something in his voice made her shut up and accept his viewpoint. It didn't mean she agreed with him one bit, but there was really no point in stirring things up that were better left alone.
Before he could pull the present out, Penelope was already telling him that it was unnecessary. She was curious as to what it could be and was happy to see that it was book-shaped.
Taking it from him carefully, Penelope read the cover and grinned at the art. It was clearly quite old and Percy knew that she loved old things. They had a feel and a smell to them that made them irreplaceable. The book clearly had something to do with cooking, but she wanted to hear some about it from Percy. "How did you come by this?" she asked, examining it still, an eager-to-learn look on her face, "It's beautiful. Thank you," she leaned up to kiss him on the cheek to show her appreciation.