In a large saucepan melt the butter and add the mushrooms and the onion. Season with salt and pepper. Cook frequently stirring until the liquid from the mushrooms is evaporated, the onions are translucent and the mushrooms are golden.
Add the flour and sweet smoked paprika. Mix well and stir continuously for a couple of minutes, and add the cold vegetable stock. Mix well and bring to a boil, stirring frequently.
Once the soup thickens up, keep boiling for about 10 minutes. Then add the cream and mix well. Adjust the seasoning and garnish with fresh dill. Serve with fresh bread.