Put 1 cup sugar to caramelize, then add the remaining sugar and pour in all of the water. Stir until it melts and then remove the caramel syrup from the stove.
Heat the butter in a separate container and add the semolina. Stir energetically until the semolina browns, about 2 min.
Pour the caramel syrup over it, continue stirring until the semolina thickens. Immediately before removing from the stove, add the cinnamon and orange zest.
Pour the mixture into a cake form, smooth it out on top and put in the fridge to cool and harden. Then invert the caramel semolina halva into a platter and sprinkle with a mixture of crumbled nuts and brown sugar (optional).