Arrange the rack in the middle of the oven and heat to 350℉.

Cut 1 (2-pound) green or purple cabbage in half through the core. Cut each half into 4 wedges, keeping the core intact. Thinly slice ½ medium red onion (about 1 ¼ cup). Mince 3 garlic cloves.

Heat ¼ cup of the olive oil in a large cast iron or other oven-safe skillet over medium heat until shimmering. Tilt the skillet so the bottom is completely coated with oil. Add half of the cabbage in a single layer cut-side down. Season with ½ teaspoon of the caraway seeds, ¼ teaspoon of the kosher salt, and ¼ teaspoon of the black pepper. Sear until deep golden-brown, 3 to 5 minutes. Flip the wedges with tongs and sear until the second side is browned, about 3 minutes more.

Transfer the cabbage to a cutting board or large plate. Add the remaining ¼ cup olive oil and repeat with the remaining cabbage, seasoning with the same amount of caraway, salt and pepper. Transfer to the same cutting board or plate.

Reduce the heat to medium. Melt 2 tablespoons unsalted butter in the now-empty skillet (no need to wipe out). Add the onion and cook until softened, 2 to 3 minutes. Add the garlic and cook until fragrant, about 30 seconds.

Add ½ cup dry white wine or apple cider vinegar and cook until reduced by about half, 1 to 2 minutes.

Remove the pan from the heat. Add 1 cup low-sodium chicken or vegetable broth, 1 tablespoon whole grain Dijon mustard, 4 fresh thyme sprigs, 2 bay leaves, and the remaining ¼ teaspoon kosher salt. Stir to combine. Return the cabbage to the skillet, overlapping them as needed to fit all the wedges in.

Transfer the pan to the oven and roast for 30 minutes. Flip the cabbage wedges. Continue roasting until the cabbage is very soft and caramelized around the edges, and the liquid is mostly absorbed, 30 to 35 minutes more.