Peel, wash and quarter the potatoes. Cut bacon into small cubes. In a frying pan, leave to crisp, take out. Add oil to the bacon fat. Fry the potatoes for 10 minutes at medium heat, turning them over, and add a little salt.
In the meantime, clean and wash the mushrooms, possibly halve them. Clean, wash and cut spring onions into bite-sized pieces. Wash rosemary, chop leaves. Remove peppercorns from the panicle. Add prepared ingredients to the potatoes, season with salt again and fry for another 5-8 minutes.
Serve with a dash of crème fraîche and rendered bacon.