Roughly chop the tomatoes, celery, onions, and peppers.

Cook the vegetables in a large pot until softened.

Pass the cooked vegetables through a tomato strainer to remove skins and seeds.

Pour the strained tomato mixture back into the pot.

Place the pot on the stove and bring the mixture to a boil.

Add salt, sugar, and butter to the boiling mixture.

In a separate bowl, mix cornstarch with water to create a paste.

Slowly pour the cornstarch paste into the boiling tomato mixture, stirring constantly to prevent lumps.

Continue to boil until the soup thickens slightly and reaches a 'rolling boil'.

Carefully ladle the hot soup into sterilized pint or quart jars, leaving appropriate headspace.

Seal the jars according to canning instructions.