Soak the lentils in salted water for at 3 hours,
Drain and rinse the lentils then add to a blender with everything else apart from dried celery.Blend until smooth then stir in the dried celery.Pour onto a grease-proof paper lined baking dish and spread to the sides.
If you have a dish that fills a normal oven then this will make one batch, the more you make thin layer.faster it gets cooked in oven. So it's batter to divide in to 2 batches. Preheat oven at 180 for 15mins.Bake for 30mins