Peel the potatoes and cut into 1cm thick chips.
Mix with the oil and turmeric.
Spread out the chips on a baking tray lined with baking paper, and bake in the preheated oven at 220°C (200°C fan, gas 7) for 35 minutes, turning twice.
Toast the sesame seeds in a dry pan until pale golden.
Coarsely crush the sesame seeds with some sea salt.
Sprinkle the chips with the sesame salt and serve.