I used to be a member of a family from Norway and Sweden. They served many dishes I have fond memories of, and know how to make.
But there is one I have been searching for and cannot find. It's called tjukkmjølk or tettemelk.
This sounds interesting - apparently you can dry it out and save this to make a new batch.
You might try one of these:
translate.google.com/
Sandi, I just ran across this question and I was curious so I did a little digging. I found these interesting links that have a lot of information. No recipe but more about the ingredients and process.
www.fondazioneslowfood.com/
It sure sounds like you need to have the culture that was made with the butterwort to make it from scratch. And I can't find anyone who sells it commercially in the U.S. But I did find a comment that said that Långfil is the Swedish equivalent. And then I ran into this informative page.
nordicfoodlab.wordpress.com/
Which led me to this Amazon link for the culture:
www.amazon.com/
I can't tell if this will be exactly the same as what you had before but it is probably worth a try.
And last but not least, I found this page that appears to have a recipe for it. Unfortunately it is in Norwegian but maybe it will help.
Good luck and keep us posted. :)
Maybe a member of a Sons (and Daughters) of Norway Lodge could share a family recipe. Here is their webpage with a directory. members.sofn.com/
