Preheat oven to 400 degrees. Add tomatoes and garlic to a parchment-lined baking sheet, drizzle generously with olive oil, and season with salt and pepper. Roast for 35 minutes, or until gently roasted but not burned.
In a medium pot, add butter and onions, cooking until the onions are nicely browned and cooked down.
Add roasted tomatoes and garlic, and chicken broth. Add oregano, honey, and chopped basil, and stir. Bring to a boil over medium-low heat.
Remove from heat and blend until soup is fully pureed, using an immersion blender.
Return to medium-low heat and summer for 20-25 minutes.
Add feta cheese and blend with the immersion blender. Add salt and pepper to taste.
Top tomato soup with croutons, crumbled feta, fresh basil, and pepper.