Lightly oil an 8 cup bundt pan, or another mold of your preference.
Make the halva: In the meantime, in a large, deep pot heat the oil and semolina. Cook in medium high or high heat, stirring constantly until it gets deeper in color and starts to smell nutty. Take off the heat.
Carefully – because it will bubble a lot and may pop – add the syrup in the pot with the semolina mixture.
Return to heat, reduce to medium and stir until the mixture thickens. It should be like a cake batter, but with coarse granules.
Divide the mixture in two parts and add the chocolate into the one. Stir to combine and melt.
Spoon the batter by spoonfuls in the mold, alternating the vanilla and chocolate mixtures, pressing it firmly to fill every gap.
Let it cool for 30 minutes and invert it onto a plate. It will need a few taps to come off the mold.
Place them in a pot with te rest of the ingredients and simmer gently for 15-20 minutes until soft. Leave them in the syrup to cool.
The olive oil ganache is a bit temperamental. It will seem very runny at first, but as it gets cold it can thicken very suddently. If you put it in the fridge to cool, check it very very often. If it hardens while being in the fridge, warm it in the microwaves, in 5 sec increments.