Prepare the vegetables: peel and dice the Floury Potatoes into roughly 2 cm cubes, thinly slice the Leek (white and light green parts), dice the Carrot and Celeriac, and finely chop the Onion. Slice the Wiener Sausages into bite-sized rounds and finely chop the Chives and Parsley.
In a large soup pot over medium heat, cook the Smoked Bacon until crisp; transfer the bacon to a plate with a slotted spoon and leave the fat in the pot.
Add the Unsalted Butter to the pot with the bacon fat and melt. Add the chopped Onion, sliced Leek, diced Carrot and Celeriac and sauté gently for 6–8 minutes until softened and translucent, but not browned.
Add the diced Floury Potatoes to the pot, stir to combine, then pour in enough Chicken Broth to just cover the vegetables (about 1.2–1.5 liters depending on pot size).
Stir in the Dried Marjoram, Bay Leaf, and season with a little Salt and Black Pepper. Bring to a gentle boil, then reduce heat and simmer, uncovered, for 20–25 minutes or until the potatoes are very tender.
Remove and discard the Bay Leaf. For a silky texture, mash a portion of the soup against the side of the pot with a potato masher or pulse briefly with an immersion blender until you reach your desired consistency—leave some chunks for body.
Lower the heat and stir in the Heavy Cream and a grating of Nutmeg. Warm through gently for 2–3 minutes; taste and adjust seasoning with more Salt and Black Pepper if needed.
If you like the sausages browned, quickly sauté the sliced Wiener Sausages in a small pan until lightly caramelized, then stir them into the soup to heat through. Scatter the reserved crisp Smoked Bacon back on top.
Ladle the soup into bowls and garnish with the chopped Chives and Parsley. Serve hot with crusty bread for dipping.
