To make the halva: Heat the olive oil in a large, wide pot over medium heat, and add the semolina. Cook, stirring, until the semolina begins to brown lightly, as if you were making a roux. This will take longer than you think! -- About 12 to 15 minutes. At that point, over low heat, using a ladle and with your face far from the pot’s opening, very slowly add the syrup to the semolina mixture, stirring vigorously with each ladleful. Add the nuts, additional cinnamon, raisins and orange zest. Continue to stir the halva mixture over low to medium heat for another 15 minutes or so, until the contents of the pot peel away from the sides. Remove from heat and spoon into a bundt or jellow mold or into individual tartlet or muffin molds. Cover with a kitchen towel and let the halva set at room temperature. You can then chill it or serve it at room temperature.