Using a high speed blender, lightly puree the tomatoes. Begin by adding half of the tomatoes to the blender then as they go down during the blending process, add the remaining tomatoes. Set aside.
Into a large pot over medium high heat, add the olive oil. When the oil is hot add the carrots and onions. Cook for 3 minutes, stirring frequently until softened.
Add the tomatoes.
Bring to a boil then reduce the heat to low and simmer for 30 minutes.
In a small saucepan over medium heat, melt the butter.
Add the flour, whisking until combined.
Pour in the milk and continue whisking until the consistency is smooth.
Add the milk/flour mixture into the soup pot with the vegetables.
Stir in the vegetable broth, basil, sugar, sea salt, black pepper, celery salt, and garlic powder.
Simmer for 45 minutes, stirring occasionally.
Carefully pour the soup into the blender. Blend until smooth or to your desired consistency then serve.