Aleppo peppers are used all over the middle eat. It is lightly hot (ranking a 3 on the Scoville scale, measuring pepper heat. Just to compare, cayenne peppers are a 6). The Aleppo is also sweet and fruity. It is more humid than other chillies. You can replace it with chilly flakes in a little bit of sugar and water, or sweet oil, and for this particular recipe, a little bit of orange zest.