Pour the sugar, lemon juice and water in a container. Leave it to boil for 10 min., then leave it to cool.
Pour it into an oiled tray. On top, arrange the walnuts, cut into halves.
Place in a moderate oven and bake about 50-60 min. Take it out and cut into pieces, pour on the syrup.
Leave the Turkish cake to take in the syrup for about 2-3 hours and then serve.