Sourdough soup (White borscht)

Sourdough starter

• 150 g wholemeal plain flour
• 1000 g warm water
• 45 g rye bread (approx. 2-3 slices), cut into quarters
• 1 garlic clove, cut into slices

Soup

• 8 slices dried porcini mushrooms or dried shiitake mushrooms, cut into thirds
• 1100 g water
• 4 eggs
• 70 g brown onion, cut into halves
• 2 garlic cloves
• 20 g olive oil
• 150 g bacon, cut into cubes (1 cm)
• 100 g chorizo sausage or Polish sausage, cut into slices (0.5 cm)
• 200 g potatoes, peeled and cut into cubes (1 cm)
• 2 tbsp Vegetable stock paste (see Tips)
• 2 dried bay leaves
• 3 allspice berries
• ¼ tsp sea salt
• ¼ tsp ground black pepper
• 2 tsp dried marjoram
• 1 tsp fresh horseradish, grated (optional)
• 50 g sour cream