Gather your ingredients. Dice the smoked bacon, onion, carrot, russet potatoes, celeriac, and leek into small pieces.

In a medium-large pot, melt butter over medium heat. Add diced bacon and sauté for 1 minute until crisp. Incorporate diced onion and stir for 3-4 minutes until softened.

Add diced carrot, russet potatoes, celeriac, and leek. Stir to coat veggies with bacon and butter. Cook for another 2 minutes.

Pour in chicken stock, add parsley, dried marjoram, and bay leaf. Season with salt and pepper. Simmer for 15-20 minutes until veggies are tender.

Remove bay leaf and blend the soup until smooth using an immersion blender. Adjust consistency with additional stock or cream if desired.

Warm wiener sausages, slice them, and serve on top of the soup, garnished with fresh parsley. Serve hot.