jimm
The key is not to melt the fat.
Over 20 years I’ve tried finding a way to cook sausage and not melt the fat.
What ie found was cooking in my kitchen stove .
I set the oven for 170* and leave the sticks in for 5.5 hours. In 5.5 hours my internal temp reaches 153*, and that’s perfect so the fat doesn’t melt.
I then submerse them in an ice water bath.
I’ve done this and the fat stays marbled.
Weather you use pork fat or butts it doesn’t matter, it’s all about temp.