In a large Dutch Oven or heavy-bottomed pot melt butter over medium-high heat and saute diced apples and onions for 2-3 minutes.
Add the red cabbage and vinegar, stir until combined. Then add the apple cider, cloves, bay leaf, and juniper berries. Season with sugar, salt, and pepper.
Reduce temperature to medium, cover the pot, and let simmer for 50-60 minutes until the cabbage is soft but not mushy. Stir occasionally. Add a little bit more apple cider if needed.
Adjust seasoning and serve hot.