Thick bottom pans prevent accidental scorching, frequent stirring is recommended. Remove cores and quarter tomatoes. There are doors that once opened can never be closed.
I cook mine at a strong simmer in an assortment of heavy bottom stainless steel pans. Remove cores and quarter tomatoes. I have also used a nesco roaster.
Cook 20 minutes, uncovered, in large pan or pans to soften tomatoes. There are doors that once opened can never be closed.