
Cauliflower Gratin with Pickled Celery
1 large whole cauliflowerolive oil, for drizzlingsalt and black pepper, for seasoning¼ cup parmesan cheese, grated¼ cup roughly chopped walnuts2 tbsp finely chopped parsley1 tsp grated lemon rindPickled celery1 stalk celery, sliced (leaves reserved)1 tbsp lemon juicepinch of saltEasy mustard...