Preheat oven to 200°C and line a large oven tray with baking paper.
In a bowl, whisk together the melted butter, miso paste, garlic, rice vinegar, and sesame oil (if using) until smooth.
Arrange cabbage wedges in a single layer on the tray, cut side down. Spoon or brush the miso butter generously over each wedge, turning to coat both sides. Reserve a little miso butter for finishing later, if desired.
Roast cabbage for 25–35 minutes, turning halfway, until the cabbage is tender, golden, and crisp at the edges. If the edges are browning too fast, reduce the heat slightly.
Served brushed with remaining miso butter and sprinkled with sesame seeds, chilli and or a squeeze of lemon or lime juice (if using).
