Clean the mushrooms, wash briefly, dab dry and cut into slices. Peel and finely dice onions. Peel, wash and coarsely dice the potatoes.
Heat the oil in a wide saucepan. Sauté the mushrooms, except for 2 tbsp, for 2-3 minutes, turning them. Fry onions, potatoes and marjoram briefly. Season with salt and pepper. Add 800 ml water, bring to the boil, stir in broth and simmer covered for about 20 minutes.
In the meantime, halve the bacon for the bacon plums. Wrap 1 piece of bacon around each plum. Heat a pan without fat. Fry the bacon plums until crispy all around. Put 2 plums on each skewer.
Fry the remaining mushrooms in the bacon fat. Season with salt and pepper. Finely puree the mushroom soup. Add cream and bring to the boil. Season to taste with salt and pepper. Garnish with mushrooms. Serve with skewers. Baguette tastes good with it.