Boil the diced potatoes and carrots in salted water for 5 minutes, then drain.
Fry bacon lardons and leftover meat in vegetable oil over medium-high heat until seared.
Melt butter in the pan, add onions, and cook for 5 minutes while stirring.
Add potatoes, carrots, and sausage, then fry for 5 minutes.
Add fresh mushrooms and thyme, cooking for a few additional minutes.
Finely chop soaked mushrooms and add them to the pan with 50ml of soaking liquor.
Season and cook until a brown crust forms, scraping the base of the pan regularly.
Divide into 6 portions, top each with an egg yolk, and serve with garnish and jam.