1. Heat the oil over medium high heat. Sear the salmon skin-side down for six minutes, then flip and sear for six more minutes. Remove the salmon and set aside.
2. Add in the white and shiitake mushrooms and sauté for a few minutes until the mushrooms are a deep golden color. Add the garlic and sauté for thirty seconds. Pour in the heavy cream, white wine, truffle oil, salt, and pepper. Simmer for five minutes.
3. Add the gnocchi, spinach, and flake the salmon into the pot. Mix well and cook for an additional five minutes for all the flavors to mesh.