Place the potatoes into a large mixing bowl and top with the harissa, garlic and olive oil
Season generously and toss to combine
Place onto a large lined baking tray, spreading them out as much as possible
Cover tightly with tin foil then place into the oven for 15 minutes
Remove the foil, reduce the temperature to 200° Celsius and roast for 25 minutes
Remove from the oven and transfer the potatoes and any pan juices to to a serving bowl
Add the sesame seeds and toss to combine and serve with the dressing on the side
for the dressing
Place the tahini, soy, mirin and vinegar into a small mixing bowl
Whisk well to combine and place into a small jug or bottle
Drizzle as much as you want over the potatoes and store in a sterilized glass jar if you have left overs
Notes
See this post on how I sterilize my glass jars. According to Yotam, you can use maple syrup instead of mirin. I substituted apple cider vinegar for rice vinegar.