Directions: 1. Preheat oven to 190C (375F, Gas 5). Line the base and sides of a 20cm round cake tin with greaseproof paper and brush with the melted butter.
2. Cook the potatoes in a pan of lightly salted boiling water for 6-8 minutes until tender. Drain and pat dry with kitchen paper. Wipe out the pan and return to the heat.
3. Add the oil and fry the leek and the thyme for 4-5 minutes, stirring occasionally, until softened and just beginning to turn golden.
4. Layer up the potatoes and leek mixture alternately in the prepared tin, seasoning between each layer.
5. Beat the eggs and milk together and pour over the leek and potato layers.
6. Bake for 35-40 minutes until golden and firm to the touch.
Turn out and peel off the lining paper.