Cut cabbage into sturdy wedges and roast until just tender and slightly caramelized. While the cabbage cooks, whisk together the miso butter sauce to drizzle over the finished cabbage. It's delicious!
Cut the cabbage in half through the core. Cut each half into 4 wedges that are about 1 to 1 1/2-inches each. It's ok to leave some core to hold the wedges together, but if there is an excess, just trim it away. Lay the wedges on a baking sheet lined with parchment paper or a silicone baking mat. Drizzle 1 tablespoon olive oil over the cabbage and use your hands to rub it over the surface. Sprinkle the salt over the top.
Roast until the cabbage is just tender with edges that are browned and a little crispy, 20-25 minutes.
While the cabbage roasts, heat 1 tablespoon olive oil in a medium skillet over medium heat. Add the scallions and sauté until a little tender, 2 minutes. Add the butter, ginger, brown sugar, vinegar, and water and whisk until the butter melts. Remove from heat, add the miso, and whisk just until creamy.
When the cabbage is done, drizzle the warm miso butter over the cabbage. Scatter the nuts over the top. Serve immediately.