You're the cream to my crop

When someone says "you're the cream to my crop" it means without them you wouldnt havw grown into the person you are today. Hense when water (cream) is added to a plant (crop) it flourishes and becomes the beautiful flower that it was born to become. This is a compliment.

Jillian: Happy Birthday to my best friend, you're the cream to my crop and I love you.

Lizzy: cream to my crop?
Jillian: yes. It's a compliment.