In a large stockpot, melt 2 tablespoons of butter over medium heat then add in the sage leaves to crisp up for about 30 seconds. Remove and set aside.
Then add in the shiitake mushrooms. Sauté for 3-5 minutes or until golden brown and lightly crispy. Remove from the pan and set aside.
Add in the remaining 2 tablespoons of butter, shallot and garlic and sauté until soft and aromatic, about 5 minutes.
Then add in the sliced mushrooms and continue to cook for 10-12 minutes until they're soft and beginning to caramelize.
Add in the Dijon mustard and flour and cook for 1-2 minutes.
Pour in the marsala wine to deglaze the pan, making sure to scrape up any browned bits on the bottom of the pot!
Add in the vegetable stock, thyme, sage, salt, pepper, nutmeg, and cayenne. Reduce the heat and simmer for 15-20 minutes or until the soup has thickened slightly.
Then stir in the heavy cream and cook for another 5-10 minutes, until heated through. Taste and adjust seasonings if needed.
If desired, you can then puree the soup for an even creamier consistency! You can use either an immersion blender or a standard blender to get the soup nice and smooth! If using a standard blender, you'll need to blend in 2-3 small batches. Only fill the blender about halfway and leave the hole in the lid open to allow steam to escape.
Ladle the cream of mushroom soup into bowls and top with the crispy shiitakes and sage.
Condensed Mushroom Soup
Reduce the amount of vegetable stock to 1 cup and reduce the amount of heavy cream to ½ cup.
Follow the instructions as written up to step 6. Then add in the reduced amount of vegetable stock, heavy cream, herbs and spices. Reduce the heat and simmer for 5-10 minutes or until thickened.
Use 1:1 to replace canned cream of mushroom soup!
Notes
Store in an airtight container in the fridge for up to 5 days!