Finely chop the onions and garlic. Cut off the upper quarter of each of the marjoram stalks and set aside, pluck the remaining leaves and chop finely. Peel potatoes. Peel the pears, remove the core and quarter. Cut the pears and potatoes into approx. 1 cm pieces.
Melt the butter in a saucepan, fry the onions, garlic, marjoram, pears and potatoes vigorously for 2 minutes. Pour in the wine and let it boil down. Top up with the stock and cream and cook over medium heat for about 20 minutes. Finely puree the soup with the hand blender and strain through a sieve into another saucepan.
Bring to the boil once, season with salt and pepper. Place 2 slices of duck breast lengthways on skewers. Serve the soup in preheated plates with 1 skewer each, marjoram tips and pear chips.