https://www.thepauperedchef.com/article/wisconsin-style-bratwurst

My little adventure with bratwurst reached its pinnacle after a tortuous three hour process of grinding, mixing, stuffing, poaching, and charcoal grilling. What I faced, fortunately, looked a lot like the bratwurst of my wildest fantasies. It was perfectly plump, gushing with juice, and absolutely haunted by charcoal smoke. I stuffed that sausage into a huge roll and piled it high with sauerkraut and grainy mustard. The meat was layered with spices like nutmeg and ginger, and had a major snap from the hog casings. My homemade bratwurst had worked.

• 4 pounds pork shoulder, cut into 1-inch cubes and stored in the freezer for 30 minutes
• 1 pound Pork back fat, chopped and stored in the freezer for 30 minutes
• 3 tablespoons kosher salt
• 1 tablespoon sugar
• 1 1/2 teaspoons grated nutmeg
• 1/2 teaspoon coriander
• 1/4 teaspoon celery seed
• 2 teaspoons ground black pepper
• 1/8 teaspoon ground marjoram
• 1 1/2 teaspoons dried ginger
• 10 feet medium hog casings

1. Cut the pork shoulder into 1-inch cubes and store in the freezer for 30 minutes.
2. Chop the fatback and store in the freezer for 30 minutes.
3. Soak the casings, especially if they are packed in salt, for at least 30 minutes, changing the water occasionally. Rinse the insides out under the faucet.
4. Set a bowl on top of another bowl filled with ice water. Collect the ground meat in here.
5. Grind the cooled meat and fat through the large die of the meat grinder. Once done, return the meat and fat to the freezer for 30 minutes or so.
6. Mix together the salt, sugar, nutmeg, coriander, celery seed, black pepper, marjoram, and ginger.
7. Mix the meat and spices together.
8. Stuff the sausages. Section them off into about 5 inch sections by twisting them.

To make 'Sconny-style brats:

1. Chop one onion and toss in a large pot. Add one can of American beer that you don't mind wasting. Bring the mixture to a boil, then reduce to a simmer.
2. Add a few of the sausages (I saved well over half for later), and gently poach for 20 minutes. Do not let boil!
3. Cook the bratwurst over the hot side until nicely browned on all sides. Let cool a bit, the juice inside will be hot!