Which seasonings would you add to this soup?

The Mrs. wanted a vegan soup so I improvised based on something I'd seen from Lidia Bastianich and what we had in the house. The below was spiced with cayenne, salt and pepper; thyme was also used. It turned out great, but I know I could be more creative with it. What say the chefs of the F&D Board?

Cauliflower and Tomato Soup

1 whole yellow onion
Enough olive oil to liberally coat the bottom of a Dutch oven
4 carrots, coarsely chopped
2 celery stalks, coarsely chopped
2 teaspoons thyme
1 6 oz can tomato paste
1 head cauliflower, broken into individual and grouped florets

Saute your onion in the olive oil and cook until translucent

Add your carrots and cook for 5 minutes

Add your celery and cook for another 5 minutes

Group vegetables off to the side to form a bare hot spot at the bottom of your Dutch oven. Add your tomato paste to this hot spot and cook, stirring as needed, until carmelized and beginning to brown

Stir the carmelized tomato paste into the rest of your vegetables and then add the thyme

Add enough water to produce the consistency you want for your soup

Cover and boil for 20 minutes, stirring as needed

Add cauliflower and simmer until cauliflower becomes soft while seasoning with salt, pepper and Cayenne to taste