Instructions

1. 1

   Peel the cold boiled potatoes and cut them into slices about 5 mm thick. Clean and quarter the mushrooms, and slice the onion into thin rings.

2. 2

   Heat the oil in a large pan until hot. Add the potato slices in a single layer and fry without turning too soon, until the underside is golden and crisp, then flip.

3. 3

   Add the onions and mushrooms, stir in the butter and keep frying briskly until the mushrooms are nicely browned.

4. 4

   Season with salt and pepper, scatter with chopped parsley and serve at once.