In a large pot, melt the butter over medium-low heat. Add onions and cook gently until soft and translucent, about 15 minutes.

Add flour and stir to combine until slightly pale gold, do not allow to brown.

Stir in the tomatoes, chicken broth, sugar, salt, celery salt, and pepper. Rise heat to medium until it starts to boil then reduce heat to low. Simmer for 30 minutes, scraping the bottom of the pot frequently.

Stir in torn basil, heavy cream and honey. Remove from heat and puree with immersion blender or in batches in a standing blender until smooth. Top with drizzle of heavy cream and more fresh basil.