To make the salsa, start by brushing two capsicums all over with olive oil. Char them over an open flame (i.e. a gas stove) until completely blackened. Place in a bowl and cover with cling film for 30 mins, before peeling away skin with hands. Remove seeds and chop the capsicum into small squares.
Combine all other veggies into a bowl. In a separate bowl or jug, whisk to combine olive oil, vinegar, salt and pepper and ground cumin. Pour over the veggies and set aside for at least 2 hours before serving.
For the lamb: Preheat oven to 220c (200c if fan forced). In a bowl, combine all dry spices and olive oil. Stir until it becomes a thick dry paste. Rub spice mix and coat trim lamb roasts generously. Place on a wire rack over an oven tray.
Place lamb in the oven and immediately reduce oven heat to 180c (160c if fan forced). Cook for 20-25 minutes. Remove from oven, allow to rest for 10 minutes before slicing up and serving on warmed naan bread topped with yoghurt, your premade salsa criolla, and fresh herbs. Enjoy!
