At the barbecue, this quickly became the most popular dish. My sister made it, and everyone kept asking about the secret ingredient.

Instructions
Add the Kielbasa: Place the sliced sausage in the slow cooker.
Make the Sauce: In a bowl, combine the diced apples, brown sugar, Dijon mustard, apple cider vinegar, cinnamon, and nutmeg.
Assemble: Pour the apple mixture over the sausage.
Top With Onion: Sprinkle the chopped onion over everything.
Cook: Cover and cook on low for 4–6 hours, stirring now and then, until the apples soften and the sausage becomes coated in glaze.
Serve: Add fresh parsley if desired and enjoy warm.

Tips & Custom Options
Add Heat: Mix in smoked paprika or red pepper flakes for a spicy version.
Make It Milder: Reduce the vinegar and mustard if serving to younger or selective eaters.
Sweet Upgrade: Stir in dried cranberries or raisins during the last hour for extra sweetness and texture.