Preheat the oven to 180°C
Line a baking tray with nonstick baking paper
Place all the ingredients for the shiitake marinade in a bowl and whisk until thoroughly combined; it will form a stiff paste
Cut the cabbages in half through the cores and place on the lined tray
Spoon one-quarter of the marinade on the cut side of each cabbage and use the back of the spoon to press it into all the crevices, ensuring the cut side is evenly covered
If any areas look a little dry, give them a drizzle of olive oil
Toast for 30-35 minutes until the marinade is starting to look caramelised and you can slide a knife easily through the cores
For the sauce, place all the ingredients except the oil in a jug and use a stick blender to blitz it into a fine paste
With the blender still on, slowly add the olive oil, a trickle at a time, until it's all combined and you have a thickened, pale yellow sauce
Make the spiced parsley by stirring all the ingredients together in a small bowl
Smooth the pilpil sauce onto a serving dish, top with the warm cabbage halves sprinkled over the spiced parsley to serve
