Why did my almonds burn instead of caramelizing?
Right off the top of my head, I would have to say that it had to do with the toasting OR the size of the nut. If you toasted the halves longer than you normally would, if they were a darker brown color, then it would take less time for them to burn. Then you mentioned Whole cashews vs. halved almonds. The thickness of the individual pieces is also going to affect how fast they cook through (and then burn). Then there's the fact that your hazelnuts (also thicker than halved almonds) turned out ok. 

If you REALLY REALLY want to make this recipe with almonds, I'd almost suggest not toasting them at all...or very, very lightly.