Beer Simmered Bison Bratwurst with Sautéed Onions and Sauerkraut

3 pounds High Plains Bison Bratwurst
1 onion, thinly sliced
3 cups beer, as needed
About 1 tablespoon vegetable oil
Mustard, for serving
12 large Bratwurst buns

1. Prick each sausage a half-dozen times with a fork. Arrange the onion slices on the bottom of a sauté pan just large enough to hold all the sausages. Place the sausages on top and add beer and water to cover (the ratio should be about 3 parts beer to 1 part water). Place the pan over medium heat and gradually bring the liquid to a simmer, not a rapid boil. Poach the sausages 4 to 5 minutes. Transfer the sausages to drain in a colander.
2. Set up the grill for direct grilling and preheat to medium-high.
3. Grill Bratwurst over medium heat until crisp and nicely browned 4 to 6 minutes per side.
4. Transfer the sausages to plates or a platter and let rest for 3 minutes. Serve with plenty of mustard, and large bowls of sautéed onions and hot sauerkraut, use the bagged variety and not the canned it's much better!

Serves 8-12