Step 1

Heat a large cast-iron skillet or high-sided saute pan over medium-high heat. Add the oil and swirl the pan to coat evenly. Add the sausage slices in a single layer and cook until browned on the first side, about 2 minutes. Flip and cook until browned on the second side, about 2 minutes. Use a slotted spoon to remove the sausage slices to a bowl and set aside.

Step 2

Add the onion, a splash of water and large pinch salt to the pan and cook over medium-high heat, using a wooden spoon or heatproof rubber spatula to scrape up any browned bits from the bottom of the pan. Cook, stirring occasionally, until the onion is lightly browned in spots and starting to get tender, 5 to 7 minutes. Add the cabbage, crushed red pepper and another pinch salt and cook until cabbage is crisp-tender, 6 to 8 minutes, stirring occasionally. If the pan seems dry at any point, stir in another splash of water.

Step 3

Add the garlic and cider vinegar and cook until the vinegar is mostly evaporated, about 1 minute, stirring constantly. Stir in the butter until melted, then return the sausage to the pan along with the apple and cook until the apple slices are just tender, 3 to 4 minutes, stirring occasionally.

Step 4

Sprinkle with the scallion and serve immediately with hot sauce alongside.