1. In a stockpot, over medium heat, combine the tomatoes, onion, cloves and chicken broth. Bring to a boil, and gently boil for about 20 minutes to blend all of the flavors. Remove from heat and run the mixture through a food mill into a large bowl, or pan. Discard any stuff left over in the food mill.
2. In the now empty stockpot, melt the butter over medium heat. Stir in the flour to make a roux, cooking until the roux is a medium brown. Gradually whisk in a bit of the tomato mixture, so that no lumps form, then stir in the rest. Season with sugar and salt, and adjust to taste.

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