- In a saucepan, over medium heat, bring the beer up to a simmer. Add the brats, and cook until plump, about 6 minutes.
- Preheat the grill.
- Lightly brush the sausages with oil. Place on the grill, and cook for a few minutes on each side.
- Remove the sausages from the grill, and serve with potato salad, rolls and mustard.
- Place the potatoes in a second saucepan, and cover them with salted water by 2 inches.
- Place the saucepan over medium heat, and simmer the potatoes until tender, about 15 minutes. Drain well, and return to the saucepan to keep warm.
- In the meantime, grab a skillet and cook the bacon until crispy over medium heat. Add the onions, and season with pepper. Sauté for 1 minute. Remove from the heat. Set aside.
- Transfer the potatoes and the bacon mixture (including the fat) to a large mixing bowl. Add vinegar (to taste), mustard, eggs and green onions. Season with salt and pepper. Mix well. Using the back of a spoon, mash the mixture together.