Heat oven to 450 degrees F. Line a baking sheet with foil or parchment paper, and set aside.
Cut cabbage half into four equal wedges and place on the prepared baking sheet. Use a pastry brush to coat the cut side of each wedge with oil and sprinkle with salt and pepper. Flip wedges and brush the other side with oil, and season with salt and pepper.
Place the baking sheet in the oven and cook for 10-12 minutes. Flip the wedges and roast until nicely browned, about 8-10 minutes longer.
Meanwhile, add all the sauce ingredients to a small saucepan and cook over medium heat, stirring until the butter is completely melted, and the ingredients are well-combined. Keep warm until ready to serve.
Serve wedges with sauce drizzled on top and chopped parsley, if desired.