- If you’re using dried porcini, soak them first in hot water or broth for about 15 minutes until soft. Once rehydrated, drain them and continue with the recipe as written. 
- Clean the fresh porcini gently with a brush or damp cloth and slice them into larger pieces — they’ll shrink as they cook. Prepare the rest of the vegetables: peel and dice the potatoes into small cubes, slice the carrots thin, finely chop the onion, and crush the garlic. 
- Warm a mix of olive oil and butter in a large pot. Add the onion and garlic and let them cook slowly until soft, fragrant, and golden. This forms the flavor base of your soup. 
- Stir in the carrots and cook for a minute or two so they release their sweetness, then add the porcini. Keep stirring while they fry gently (you want them to caramelize just a little). 
-  Add the potatoes and pour in enough vegetable broth (or water) to fully cover the ingredients.  
- Once the soup comes to a boil, lower the heat, cover with a lid, and let it simmer slowly for about 30 minutes. 
- When the potatoes and carrots are tender, pour in the white wine and let everything simmer for another five minutes. 
- Take out a few spoonfuls of potatoes, mash them with a fork, and stir them back in. This will thicken the soup naturally without needing flour or starch. 
- Stir in the sour cream (or cooking cream, if you prefer a milder taste). At this stage, you can blend the soup with a hand blender for a smooth texture or leave it rustic with visible chunks. 
- Finish with a handful of fresh parsley and give it another minute to mingle with the flavors. Serve the soup hot with garlic croutons or homemade bread.