In a small pot bring to a boil the 3 cups water, 3 cups grape juice, 1/2 cup of sugar and the 2 cinnamon sticks.
Once the sugar has dissolved, remove from heat and set aside.
Prepare your bundt pan by spraying it lightly with cooking spray and sprinkle the bottom with the sesame seeds. Set aside.
In a large pot, combine the 1/2 cup vegetable oil, 1/2 cup olive oil, and the 2 cups of coarse semolina.
Cook over medium heat, stirring constantly to ensure that your semolina does not burn. Cook until the semolina is a light brown colour and it smell toasty.
Add the 1 cup of chopped walnuts and cook along with the semolina for a minute. Remove from heat (but leave the element on).
Very carefully add a ladle full of the water / grape juice liquid at a time to the cooked semolina. It will bubble and splatter initially. Slowly transfer all of the liquid to the semolina.
Reduce heat to low medium and cook, stirring constantly, until the semolina thickens. When you run a spatula across the bottom of the pot you will notice the semolina separating and slowly coming back together.
At this point, remove the pot from the heat and stir in the 1/2 cup of petimezi or grape syrup / molasses.
Once the petimezi is fully incorporated, transfer the cooked semolina to your prepared bundt pan. Be sure to press down with the back of a spoon every so often to ensure that your halva takes the form of your pan - this is particularly important if your mould is intricate.
Allow the halva to cool slightly and then transfer to the refrigerator until fully cooled and set.
To serve the halva carefully invert your mould onto a serving platter or plate - the halva should come right out.
You can drizzle with some additional petimezi if desired, and some chopped up walnuts.
Enjoy!