In a large pot, melt the butter over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes.

Stir in the minced garlic, sliced mushrooms, thyme, paprika, soy sauce, salt, and pepper. Cook for another 5-7 minutes until the mushrooms are tender.

Sprinkle the flour over the mushroom mixture and stir well to combine. Cook for 1-2 minutes to eliminate the raw flour taste.

Gradually add the vegetable broth, stirring continuously to prevent lumps. Bring the mixture to a boil, then reduce the heat and let it simmer for 15 minutes.

Stir in the milk and let the soup simmer for an additional 5 minutes. Adjust seasoning with salt and pepper as needed.

Serve hot, garnished with fresh parsley.