Toast the sesame seeds on a medium-low heat until golden brown. This can take anywhere from 4-7 minutes. Then leave aside
Place the 1/2tsp of oil in the pan and toast the dried chillies for several minutes on medium-low heat until they’re slightly puffed up and turning darker. Skip this step if using chilli powder/paprika
Allow the chillies to cool, then blitz in a spice grinder until coarsely ground
Next, add the sesame seeds to the grinder (with the chilli still in there), and continue to blitz until coarsely ground. Avoid over-blitzing as the heat from the spice grinder will cause the sesame seeds to release their oils, thus forming a paste rather than a spice mix
Transfer the spice mix to a bowl and add the chaat masala, mango powder, garlic powder, and salt. Mix to combine
Pre-heat oven to 200’C (fan) or 220’C (conventional)
In a large roasting tray combine the potato wedges, 4tbsp of oil and the sesame spice mix. Toss till evenly coated and then assemble in a single layer (as best as possible)
Bake for 40-45 minutes, tossing every 10 minutes until the wedges are golden brown and crisp
As soon as they are done, add the coriander and spring onions and toss once more
Serve immediately