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

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