I'm testing out a meatball recipe with aleppo pepper flakes, and although it's good, I want a little more heat. Do you think adding a touch of cayenne would do the trick? Would it pair well with the aleppo or could it possibly overtake the aleppo's unique flavor?
Try it & see ;)
Aleppo isn't particularly hot; I haven't checked it on the Scoville scale, but just from experience, though it's got a little kick to it, & that kick can be quite variable depending on your source of the pepper, to me, aleppo is used for its flavour rather than its kick.
Cayenne, on the other hand, I always consider to be "free heat". Its largest contribution is to add the 'burn', it doesn't really have much flavour, it's mainly heat.
I always think that by the time you can actually taste cayenne, you have other concerns ;)
On an anecdotal note - I always put a little cayenne in meatballs & most tomato sauces that would go with them. It's just a family 'thing' - we like it that way.