In a frying pan, fry the onion in a little of the vegetable oil for a few minutes until it is softened. Add the chicken & the water, cover then cook for 45 minutes in a medium heat or until the chicken is cooken through, turning the thighs from time to time.
Preheat oven to 190c / 375f/ GM5.
Discard the chicken skin, remove the meat from the bones & place the pieces in a bowl.
Pour the saffron or ground nutmeg paste over the chicken, then stir in the grated cheese and 2-3 tbsp of water to make an 'unctous mixture'. Stir in the beaten eggs & season with the salt & pepper to taste.
Generously oil an ovenproof pie or quiche dish about the same zie as the rounds of phyllo. Overlap 5 sheets so that at least 1/3 of the phyllo is allowed to hang over the sides of the dish, remembering to lightly brush each sheet with the vegetable oil. Place a final 6th piece of phyllo over the top of the others - this one should be central so that it reinforces the base a little.
Pour in most of the chicken mixture, followed by a layer of sliced ricotta then a final layer of the chicken.
Fold the overhanging phyllo pastry over the top so that is wrapped but not too tight. Stick the edges together using a pastry brush & the glaze. Place another sheet of phyllo on top, tucking the edges into the dish, followed by 4 more sheets of phyllo, being sure to brush them with the glaze as you go. Finish by brushing more g;ase on the top.
Place the tagine on a low shelf in the oven for around 20-25 minutes. The pastry should be crisp & deep golden when the dish is ready.
Serve hot, on a flat dish & cut into slices as you would a cake.