I used Rose Harissa paste which wasn't overly hot, but be careful when mixing with bare hands as you can come away with a stain. I used 12% fat mince to try and keep the meatballs moist, but I think cooking them for the full 15 minutes overdid them and they were a little tough. Very satisfying combo of couscous and seasoned yoghurt. I made a double batch of the meatballs to have some in the freezer for future and it's relatively simple to make enough for a single portion if you use the 1/2 pepper in a salad the next day.
