Potato and mushroom persillade

Method

1. Drop the potatoes into a pan of boiling salted water and simmer for 4 minutes until just tender when pierced with the tip of a sharp knife. Drain well and, when they’ve dried a little, return them to the pan. Shake the pan gently to roughen up the edges slightly.
2. Heat 3 tbsp of the duck or goose fat (or 25g butter and 1½ tbsp olive oil) in a large, non-stick frying pan. Add the potatoes and fry over a medium-high heat, turning them as they colour, for 10-15 minutes until crisp and golden brown.
3. While they’re cooking, heat another tablespoon of the duck/goose fat (or 15g butter and 1½ tsp oil) in a small non-stick frying pan, add the onion and fry gently for 10 minutes or until lightly golden brown. Meanwhile, put the parsley leaves and garlic on a board and finely chop together.
4. Tip the potatoes into the pan with the onions, mix them together well, then leave to cook gently for 2-3 minutes. Heat the remaining duck/goose fat (or butter and oil) in the now empty frying pan over a high heat, add the mushrooms and some seasoning, then fry for 2-3 minutes, turning, until lightly coloured on both sides.
5. Add the potatoes and onions to the mushrooms, along with the chopped parsley and garlic mixture, then toss everything together briefly over a high heat. Season to taste and serve, topped with a fried egg if you wish.