Add about 2 tbsp oil to a large pan (best if it has a lid, but not essential). Heat over medium heat.
Add diced onion and sausage rounds and sauté until the sausage is beginning to brown and the onion is soft and golden.
Add the peppercorns (start with 1 tbsp and if you want more you can add them in toward the end, you don’t want to overdo it). Cook for about 1 minute.
Add the drained sauerkraut to the pan and stir to combine.
Add the chopped apple and 2 tbsp brown sugar. Stir. Cover and let cook, stirring occasionally, for 10 minutes.
Remove lid and taste. If it is too sour for your liking, add more brown sugar. This really is a preference thing. You can also add more peppercorns now too, if you like.
Cover and cook about 10 more minutes, or until the apples are soft and the flavours are all melded together.
Serve with grainy mustard on the side.
Enjoy!