Heat a heavy bottom pan over medium high heat. Add your butter to the pan, once the butter has melted add your mushrooms. Cook the mushrooms for about 5 minutes, the mushrooms will begin to sweat and release their juices, continue to cook until the liquid has evaporated and the mushrooms are cooked through. Remove the mushrooms from the pan and set aside in a small bowl. Next, add the olive oil, add the chopped onion and garlic to the pan and season with salt and pepper. Sauté for 5 to 8 minutes until everything is nicely cooked through. Add the white wine to deglaze the pan, use your wooden spoon to scrape all the bits off the bottom of the pan, once the wine has mostly evaporated, add the mushrooms back in to the pot along with the veggie stock and miso paste. Bring the soup to a boil, season with salt, pepper and a pinch of chili flakes. Turn the heat down to simmer and cook for another 15 min. Using an immersion blender or an upright blender blend the soup to a puree. Enjoy.