- Place the sliced onions in a medium saucepan over medium heat and cover with lid. Occasionally stir with a wooden spoon until the onions are caramelized in a golden brown color. Once caramelized, set aside in a mixing bowl.
- Next in the same saucepan, place the mushrooms and cover with lid to cook. Occasionally stir until softened.
- Add the caramelized onions to the mushrooms in the saucepan and give it a quick stir.
- Add water just enough to be at the same level or barely submerge the onion and mushrooms. Bring it to simmer and turn off the heat.
- Pour the contents into a blender. Using the soup setting, blend the contents until smooth. (Be very careful, it's very hot! Be sure to hold the blender lid while blending for that extra precaution.)
- Pour the soup back into the saucepan over no heat. Add salt, thyme, and dill and give it a quick stir.
- Serve the soup using a ladle.