Cheese and Lentil Gratin

This is nicest with salad/vegetables or some kind of sauce I think, as it's quite dry on its own. It's yummy and healthy!

1 tablespoon oil
1 onion, chopped
1 carrot, chopped
1 celery stick, chopped
6oz red lentils
3/4 pint water
1 clove garlic, crushed
salt and pepper
4 oz cheddar cheese, grated
2 tablespoons chopped parsley
1 egg, beaten
2 tablespoons sesame seeds

Gas mark 4 for 45 minutes.

-Heat the oil in a pan and add the onion and fry until softened.
-Add the carrot, celery, lentils, water, garlic and salt and pepper to taste.
-Cover, bring to the boil and then lower the heat and simmer gently for about 20 minutes, until water is absorbed.
-Add 3/4 of the cheese, the parsley and egg to the lentil mixture. Stir until mixed.
-Spoon into a 1 litre shallow ovenproof dish and smooth the top.
-Sprinkle the sesame seeds and remaining cheese over the top.
-Bake in a pre-heated oven 180C, Gas Mark 4 for 45 minutes until topping crisp and golden brown.