Wash and core fresh tomatoes
Score a small X on the bottom of each tomato
Blanch tomatoes in boiling water for 30 to 60 seconds
Transfer tomatoes to ice water
Peel off the skins
Chop the tomatoes into chunks
Heat a pot over medium heat
Add butter or oil
Add chopped onion and cook until softened
Add tomatoes to the pot
Add salt and pepper
Add a little sugar if needed
Add optional garlic, herbs, or celery
Stir and bring to a gentle simmer
Cook uncovered for 20 to 30 minutes
Stir occasionally
Mash lightly if desired
Adjust seasoning to taste
Serve hot or use in recipes