Peel 1.5 kg sweet potatoes and cut them into sticks of about 10 cm length. Place in cold water for about 30 minutes. Lift out the potatoes and dab dry well.
Heat 2 litres of frying oil to 180 °C in a deep fryer or large pot. Put 120 g starch in a large, flat bowl. Roll sweet potatoes in it. Fry in portions for 5-7 minutes.
Carefully lift the sweet potato chips out of the hot fat with a skimmer. Drain briefly on kitchen paper. Mix 2 tsp salt and 1 tsp sweet paprika. Briefly toss the fries in a large bowl with the spice mix. Serve with barbecue ketchup, for example.