Preheat oven to 450°F. Line a rimmed baking sheet with aluminum foil or Release. Drain tomatoes, reserving the juice. Seed tomatoes, and spread in a single layer on the foil. Sprinkle evenly with the brown sugar. Bake until all liquid has evaporated and the tomatoes begin to color, about 30 minutes. Let the tomatoes cool slightly.

Cook chopped onion, chopped celery, and minced garlic in a large Dutch oven until tender, about 10 minutes. Add the flour and cook, stirring constantly until thoroughly combined. Gradually add the reserved tomato juice, chicken broth, chicken base and tomato paste. Whisk to combine. Add basil, oregano and thyme. Bring to a boil; reduce heat to low, and cook covered for 30 minutes (Note: This can be done while the tomatoes are cooking in the oven.) Add tomatoes; cook covered for 30 additional minutes. Cool mixture slightly.

Strain the mixture into a medium bowl; rinse out the Dutch oven. Transfer the tomatoes and solids in the strainer to a blender; add just enough of the strained liquid to puree until smooth. Combine the pureed mixture and remaining strained liquid in the Dutch oven; mix well. Add the sherry and whipping cream, stirring to combine. Season to taste with salt and pepper. Yield: 6 servings.