Slice the fresh mushrooms and chop the onions and garlic. Have all ingredients ready before starting to cook.
In a medium-sized pan, heat the butter over medium heat. Add the onions and garlic and sauté until they are soft and slightly golden, about 3 to 5 minutes. Make sure to stir frequently to avoid burning.
Add the mushrooms to the pan and mix with the onions and garlic. Season with salt and pepper to taste. Cook the mushrooms over medium heat, stirring occasionally, until they are soft and slightly golden about 10 to 15 minutes. Let it cool a little.
In a separate pan, mix the wheat flour with the chicken broth until fully dissolved. Add the mushroom mixture to the pan and mix well. Bring the soup to heat and cook over low heat, stirring constantly, until it begins to thicken about 10 to 15 minutes.
Add the heavy cream and lemon juice to the soup and mix well. Season with salt and pepper to taste if necessary. Continue cooking the soup over low heat, stirring constantly, for another 5 minutes until it is hot.
Serve the hot soup sprinkled with chopped parsley. Serve immediately and enjoy!