01 -
Preheat oven to 450 degrees F and lightly grease a large baking sheet.
02 -
In a large bowl, combine tomatoes, onion, and garlic. Toss with olive oil, salt, and pepper until evenly coated.
03 -
Spread tomato mixture on prepared baking sheet and roast for 15 minutes. Stir, then roast another 15 minutes, using the broiler for the last 3 minutes to lightly char tomatoes.
04 -
Transfer roasted mixture to a high-powered blender, including all pan contents. Add fresh basil and blend on high until smooth, about 50 seconds.
05 -
In a large pot over medium-high heat, melt butter. Add flour and whisk until golden brown, about 30-60 seconds.
06 -
Whisk in broth and sugar. Add blended tomato mixture and whisk thoroughly. Cook over medium-low heat for 15 minutes, adjusting seasonings to taste. Optionally add cream for a creamier texture.