How to Make It
In a medium bowl, whisk all of the ingredients together. Let stand at room temperature for about 20 minutes.
In a blender, combine all of the ingredients except the salt and pepper and puree until smooth. Scrape into a bowl and season with salt and pepper.
In a large saucepan, steam the cabbage over boiling water, covered, until just tender, about 12 minutes. Transfer to a plate.
Light a grill or preheat a grill pan. Brush the cabbage wedges with olive oil and season generously with salt and pepper. Grill over high heat, turning once, until lightly charred, about 8 minutes. Transfer the cabbage wedges to a platter and serve with the seaweed anchoïade and dill sauce.