2 large Portobello mushrooms, stalks removed
1 tbsp fresh chives, chopped
2 garlic cloves, 1 finely chopped and 1 halved
2cm/¾in fresh root ginger, peeled and finely sliced into batons
4 spring onions, chopped
1 tbsp white miso paste
2 tbsp olive oil
1 tsp toasted sesame seeds
1 tbsp soy sauce
2 large slices sourdough bread