So, by popular request, the nuts and bolts of frites maison Grillou:
1. Cut some floury potatoes into chips - I reckon mine were somewhere between half to three quarters of a centimetre thick.
2 .Put the chips into cold water with a teaspoon of salt, and bring to the boil. Simmer for one minute until they're just tender to the point of a knife. Drain, spread them out on a tea towel to dry, then chill in the fridge.
3. Heat the oil - mine's two thirds colza (rapeseed) plus one third sunflower - to 130 degrees and cook the chips for 6 minutes. They should be slightly dry on the surface but not browned at all. The idea of this stage is to cook them inside so that they end up fluffy. Drain, and if you have time cool/chill them again (I cooled them but didn't have time to chill them).
4. Heat the oil again to 180 degrees and cook the chips for two to three minutes, until they're golden but not brown. Drain on kitchen paper and salt while really hot.