01 -
Heat olive oil in a large heavy pot over medium-high heat. Add butter and let it melt, swirling to combine.
02 -
Add all your mushrooms to the pot. Cook them for about 10 minutes, stirring now and then, until they brown lightly and release their water.
03 -
Scoop out one cup of the cooked mushrooms and set them aside. You'll add these back later for texture.
04 -
Lower the heat to medium. Add your shallots and garlic, cooking just until they release their fragrance, about a minute.
05 -
Pour in your stock, salt, and tarragon. Let everything simmer uncovered for 10 minutes.
06 -
Take the pot off the heat. Carefully blend until smooth using either an immersion blender or regular blender.
07 -
Stir in the cream and black pepper. Add back your reserved mushrooms. Taste and adjust the seasoning with more salt and pepper if needed.