In fact, "mussmel". I have read it. It is a name for an oatmeal fried or cooked in lard.
Similar to flour fried in a pan with butter. Diluted, also known as flour soup or burnt soup.
auch als Mehlsuppe oder Brennsuppe bekannt.

OK, I have to say the word is so available. Now it remains to correct it. Now the question arises: what should "mussdel" be? A tool, perhaps? Like fist, dumbbell, cord.....

Wie Fäustel, Hantel, Kordel.....

As I understand it now, "mussmel" is a name.
Oats fried in lard = "mussmel.
Like...
Fried corn = "popcorn".
Now the question is how does this relate to the picture and how would "mussmel" have been applied.
Purely as a thought experiment.

Small comment:
Always errors in interpretation or translation.
In the text "In the middel line: nym denn weisz gebets brot (take then white prayer bread)."
Here "gebets" = not prayer.
We say "gäbets" = given.

White bread given, not black bread.