Joanne Harris, Fran Warde
1 hr 55
By Joanne Harris and Fran Warde
This dish takes time; don’t rush it! The result is worth it: meltingly tender potato slivers topped with a crunchy, golden crust like French bread, hence the name, Pommes Boulangère.
Heat the oven to 180°C/gas 4.
Peel the potatoes and slice them very finely using a mandolin or a food processor. Slice the onions in the same way.
Butter an ovenproof dish and make layers of the potatoes and onions, with seasoning and the thyme leaves (stripped from the st