Did these tonight - a great hit.
1. Peel the celeriac, slicing off the top and bottom and sweeping down the sides with a heavy, sharp knife to remove the tough skin. Cut the celeriac into thumb-thick slices and then into fat chips.
2. Bring a very large saucepan of salted water to the boil, throw in the chips and blanch (boil rapidly, uncovered, for 1-2 minutes). Drain the chips and throw back into the saucepan. Add the oil, curry powder and sea salt. Toss until well coated.
3. Spread the chips over a large heavy baking sheet, leaving plenty of space (you may need 2 sheets). They take roughly 30 minutes to cook, so put them in the 230C/ gas 8/fan 210C oven.