Preheat the oven to 200°C.
Peel the potatoes and cut them into chunky chips (the chunkier, the better).
Place the potatoes in a pan and cover with cold, salted water. Bring to the boil and lower the heat, then cook for 2 minutes until just softening.
Drain the potatoes and place them in a large bowl.
Spray generously with low-calorie cooking spray and add a good pinch of garlic salt. Toss them in the bowl to make sure they are evenly coated, then repeat (spray, sprinkle and toss).
Spray an oven tray with low-calorie cooking spray then tip the potatoes onto the tray, spreading them out evenly.
Cook in the oven for around 30 minutes until golden brown. Halfway through cooking, flip the chips over so that they colour evenly.