Could I make this without the halvah?

I was wondering the same thing when I first saw this recipe, so I did a bit of research and determined that it's not too hard to make halvah.

If I didn't want to bother, I'd add a handful of toasted walnuts - biggish pieces to get the full benefit of their crunch. A bit of textural contrast always improves a dessert like this . . . . ;o)

If you're omitting halvah because you don't like the taste, all ok.
Don't know if you need to use chocolate chips to replace it (author says just omit). And there are already chocolate chips in the recipe. However, your choice.
Last point, if you're omitting halvah because you don't have it, but do have or like tahini, add a tahini swirl, again per author recommendation.