Heat 1 tablespoon olive oil over medium-high heat in the skillet until very hot. Add 2 ounces pancetta and cook, stirring occasionally, until crisp and rendered. Transfer the pancetta to a small dish lined with paper towels to drain.
Place 1 pound sauerkraut in a strainer and rinse well with cold running water. Lightly press the sauerkraut to force out any excess liquid. Set aside.
Carefully place 1 pound bratwurst sausages into the hot skillet and cook for 3-5 minutes, flipping occasionally until the sausages are browned (they don't have to be fully cooked yet, because they're going back in the pan to simmer). Transfer the sausage to a sheet pan.
Add 1 medium onion and 1 pound potatoes to the pan. Season with ½ teaspoon kosher salt and ¼ teaspoon black pepper and cook for 4-6 minutes until the onions soften and the mixture is fragrant. Add 1 medium apple, 1½ teaspoons caraway seed, sauerkraut, ½ cup dry white wine and ½ cup chicken stock. Stir to combine.
Transfer the sausages back to the skillet and nestle them into the sauerkraut mixture. Bring to a boil, then reduce heat to a simmer. Cover and cook for 15 minutes.
Serve with pommery or whole grain mustard. Great with a crusty piece of bread, European butter or a semi-soft cheese like Port Salut or Chaumes and chilled (Alsatian) white wine.