Fasting Mushroom Soup

Preparation

1. Soaking the Dried Mushrooms

Place the dried porcini in a small bowl and cover with 200 ml warm (not boiling) water. Leave to soak for 20 minutes. Meanwhile prepare the remaining ingredients. Once soaked, squeeze out the mushrooms and roughly chop them. Reserve the soaking liquid — strain it through a fine sieve or muslin cloth to remove any grit particles.

2. Sautéing the Onion

In a large pot (about 3 litres capacity), heat 4 tablespoons of oil over medium-high heat. Add the chopped onion and fry, stirring occasionally, for 5–7 minutes until softened and golden. It does not need to fully brown — just lose its rawness.

Add the garlic and fry for another 1 minute, stirring constantly. Garlic burns quickly so be attentive.

3. Sweating the Vegetables and Mushrooms

Add the carrot and celery and stir for 3–4 minutes until they begin to soften. Then add the fresh button mushrooms and the chopped soaked porcini. The mushrooms will release a good amount of water — this is normal. Sweat over medium-high heat, uncovered, for 8–10 minutes until the liquid has nearly evaporated and the mushrooms begin to colour.

4. Simmering the Soup

Add the diced potato, pour in 1 litre of water and add the strained porcini soaking liquid. Add the bay leaves, thyme, salt and pepper. Bring to a boil, reduce the heat and simmer, covered, for 20–25 minutes until the potato is completely tender.

5. Seasoning and Serving

Remove the bay leaves. Taste and adjust salt and pepper. If you prefer a thicker soup, use a fork or immersion blender to mash a small portion of the soup directly in the pot — this thickens it naturally without adding flour.

Ladle into deep bowls and scatter generously with fresh chopped parsley. Pairs perfectly with a slice of homemade fasting bread or crispy toast.

Tips

Depth of flavour: alongside the porcini, you can add a tablespoon of dark soy sauce (check for gluten-free if needed) or a teaspoon of tomato purée — both boost umami without affecting the fasting status.

Which mushrooms to use: button mushrooms are the most accessible, but the soup is richer with a mix of varieties — oyster, shiitake, chanterelle. Each mushroom adds a different layer of flavour.

Creamy dairy-free variant: for a thicker, creamier texture, stir 2 tablespoons of almond or soy milk (unsweetened) into the finished soup. The soup remains in the oil-fast category.

Freezing: this soup freezes well (up to 3 months). Freeze without the potato — potato loses its texture when thawed. Cook fresh potato only in the portion you plan to eat immediately.

For the Slava table: mushroom soup is an excellent opener for the fasting Slava table as it is rich and warming — guests who are not accustomed to fasting will not feel that anything is missing.