Wash and stem the tomatoes. Immerse in boiling water for 30 seconds to 1 minute Remove from boiling water and immerse in ice water. This will help separate the skin from the tomato. Pierce tomato with knife and peel off skin. Cut in half and use spoon to remove seeds. Chop into small 1/2" pieces and put in pot with stock, butter, sugar, and garlic salt. Bring to boil, then simmer for 60 minutes Remove from heat and add pinch of baking soda (my favorite part), this will fizz and help lower the acidity of the tomatoes. Pour soup in blender or food processor and blend until soup is smooth. Serve with grilled cheese.