Rich pork belly on a bed of soft braised cabbage is old-world low carb cooking. The kind of meal your great-grandmother would have made — and she was onto something.
Preheat the oven to 350°F. Pat the pork belly dry and season all sides with half the kosher salt and black pepper. Let rest at room temperature for 20 minutes.
Heat a Dutch oven over medium-high. Add olive oil and sear the pork belly, fat side down first, until deeply golden, about 5-6 minutes per side. Remove pork belly and set aside.
Reduce heat to medium. Add sliced onion and cook until softened and lightly caramelized, 6-8 minutes, stirring frequently. Add garlic; sauté 1 minute.
Stir in the shredded cabbage, remaining salt and caraway seeds. Deglaze with apple cider vinegar, then pour in chicken broth. Use a wooden spoon to scrape up any browned bits.
Nestle the pork belly on top of the cabbage. Cover with a tight-fitting lid and braise in the oven for 1 hour. Uncover and cook for 40 minutes more, basting the pork occasionally and allowing the top to crisp.
Remove from oven; let rest 10 minutes. Slice the pork belly and serve atop braised cabbage, spooning pan juices over each portion.