Step 1

Place pork in a large resealable plastic bag. Whisk lager, soy sauce, brown sugar, and 1 Tbsp. vinegar in a small bowl; pour into bag with pork and seal. Chill, turning occasionally, for at least 4 and up to 24 hours.

Step 2

Preheat oven to 400°. Heat oil in a large ovenproof skillet over medium-high heat. Remove pork from marinade, allowing any excess to drip off (reserve marinade). Cook pork, turning, until browned on all sides, 8–10 minutes.

Step 3

Transfer skillet to oven and roast until an instant-read thermometer inserted into thickest part of pork registers 140°, 10–15 minutes. Transfer to a plate and let rest for at least 10 minutes. Pour reserved marinade into a small saucepan. Bring to a boil, reduce heat, and simmer until slightly thickened, 5–8 minutes.

Step 4

Meanwhile, melt butter in another large skillet over medium heat. Add cabbage, apple, bay leaves, and 1 cup water; season with salt and pepper. Cook, tossing occasionally, until cabbage is softened, 15–20 minutes. Add remaining 1 tsp. vinegar and toss to combine.

Step 5

Slice pork and serve with cabbage mixture and sauce.