Which is correct:
Her pride and joy are ... Her pride and joy is ...
Or does the use of 'are' or 'is' in this case depend on whether the object of the sentence is singular or plural?
If you're using "pride and joy" as a set phrase, you're talking about that one thing that is dearest to you, so in that case it's singular:
My pride and joy is a restored 1964 Mustang convertible.
If you're talking about feelings, the the phrase is an ordinary compound and is plural:
Pride and joy are two infectious emotions.
It depends on the subject of the sentence:
My kids are my pride & joy.
My daughter is my pride & joy.