First, make a list for yourself of all of the things you are passionate about. Next, for each thing, list some of the reasons you are passionate about this and how it is you express or demonstrate your passion. Now, look back at what you've written. Which thing were you able to write the most about? That's your topic.
Now, free-write -- Set a timer and just start writing about that thing. Don't worry about grammar or punctuation; just write down any images, thoughts, ideas, or memories that come to mind.
Now you have your raw material. Look at what you listed and what you free-wrote. Decide what you will include in your essay. Decide in what order you will include each thing. Then write a draft of your essay.