Cut an "X" in the top of each tomato. Bring a large pot of water to a boil. Fill a large bowl or container with ice and water. Put the tomatoes in the boiling water and continue to boil for 30 to 45 seconds or until you notice that the peels are loosening where you made the "X." Immediately immerse the tomatoes in the ice water. Peel and core the tomatoes and then slice them thickly or chop them coarsely.

Peel the onion and chop it. Thinly slice the celery. Remove the seeds from the bell pepper and dice it.

Combine the tomatoes, chopped and sliced vegetables, salt, pepper, and sugar in a saucepan. Bring the tomato mixture to a boil. Reduce the heat to low and cover the pan. Simmer for 15 to 20 minutes, or until the vegetables are tender.

Stir the butter into the tomatoes, if desired.

Serve as is or with croutons.