This cream of mushroom soup is free of dairy, eggs, wheat/gluten, soy, peanuts, tree nuts, fish, and shellfish.
Place dried mushrooms in a bowl and add hot water. Let steep for 30 minutes. After 30 minutes, drain the mushrooms and reserve all the mushroom stock. Strain the liquid through a paper towel to remove any dirt or particles and set aside.
Heat beef stock and 4 cups of rice milk in a large soup pot and bring to a boil. Add crushed rice noodles and salt. Continue to boil over low heat, stirring occasionally to prevent noodles from sticking to the bottom of the pot. Continue to boil the soup until noodles disintegrate and liquid thickens, about 50 minutes.
Meanwhile, heat canola oil in a small saute pan. Add shallots, sliced mushrooms, and re-hydrated mushrooms. Saute for about 5 minutes. Add sherry and 1/2 of the reserved mushroom liquid. Continue to cook until liquid evaporates. remove pan from heat, add remaining mushroom liquid and set aside.
When soup is thick, using a hand held immersion blender, puree the soup until smooth. (Alternatively, allow contents to cool, transfer to a blender, and puree.) Add mushroom mixture.
Stir in 2 to 4 cups of rice milk to bring soup to desired consistency. Season with 1 teaspoon salt and white pepper. Serve warm.