I have an American recipe which lists a 'can of tomato sauce' as an ingredient. Does anyone know if this just means chopped tomatoes or is an actual sauce maybe onion, garlic, tomato, seasoning? Do we have an equivalent here in UK?
I pulled out some cans of tomato sauce to answer your questions. The details are listed below, but it looks like they are generally diluted tomato paste with spices. If you can get tomato paste (canned or in a tube), that should get you the consistency that you want.
The ingredients as listed on the Hunt's brand are:
Tomato puree (water, tomato paste), water, less than 2% of: salt, citric acid, spice, tomato fiber, natural flavor
Shop Rite brand (a supermarket house brand) contains:
Tomato concentrate (water, tomato paste), onion powder, garlic powder, citric acid, natural flavorings, dehydrated bell pepper
And a can of Rokeach brand (a kosher food processor) tomato sauce with mushrooms contains:
Tomato puree (tomato paste & water), mushroom, modified potato starch, peppers, cottonseed oil, sugar, onion, apple cider viengar, garlic, celery, white pepper, bay leaves and citric acid.
Canned tomato sauce in the US does not typically have 'Italian seasoning' or basil, but there is almost always some salt and/or dried spices. Even the most basic tomato sauce is going to be more than just cooked tomatoes; however, it might be a bit more runny than simply pureed tomatoes.
I can approximate the texture of canned tomato sauce by pureeing canned whole tomatoes, which are peeled and in a very runny liquid. If you are going to start with whole tomatoes, you might blanch them first and remove the skins.
Also, canned tomatoes and tomato sauce is pasteurized. Pureed fresh tomatoes would probably not be quite the same, so if your dish is not otherwise cooked, you might try cooking your puree.
I do a fair bit of cooking from American recipes, and I have always used passata or sieved tomatoes when 'tomato sauce' is called for. Never had any problems. You can get plain versions or ones flavoured with onion, garlic, basil etc.
They are available at all the major supermarkets, sometimes in the pasta aisle, but usually with the canned tomatoes and tomato puree. It comes in either a glass bottle or a small cardboard carton like orange juice.
I found out that tomato sauce used in an American recipe is passata (typically in a carton)