Preheat the oven to Gas mk 5, 375F
Cook the lentils until soft Cook the spinach until tender Drain any excess liquid from the lentils and spinach. Season the spinach with sea salt and freshly ground black pepper Spread the spinach over the base of an ovenproof dish. Arrange the sliced tomatoes on top. Pour the lentils over the tomatoes and spread to the edge of the dish. Top with non fat yogurt to cover the lot. Bake in the oven for approx. 35 minutes.
This is great with steamed new potatoes or noodles.