Step 1: Carefully clean the Lion's Mane mushroom by gently brushing off any dirt with a dry cloth. Do not wash under water, as it can absorb too much moisture.
Step 2: Using your hands, gently tear or slice the mushroom into 1-inch thick 'steaks' or large chunks. Some pieces may be naturally thicker. Aim for relatively even thickness for consistent cooking.
Step 3: Place the mushroom pieces between two sheets of parchment paper or paper towels. Using a heavy pan, gently press down on the mushrooms to flatten them slightly and remove excess moisture. This is crucial for achieving a good sear. Do not over-press.
Step 4: In a shallow bowl, whisk together tamari (or soy sauce), nutritional yeast, smoked paprika, garlic powder, black pepper, and 2 tablespoons of avocado oil to create the marinade.
Step 5: Add the flattened Lion's Mane pieces to the marinade, ensuring all sides are coated. Let them marinate for at least 10 minutes, or up to 30 minutes for deeper flavor. For best results, allow them to sit for about 15 minutes.
Step 6: Heat a large cast-iron skillet or heavy-bottomed pan over medium-high heat. Add a tablespoon or two of avocado oil, enough to lightly coat the bottom of the pan. The pan should be hot but not smoking.
Step 7: Carefully place the marinated Lion's Mane pieces into the hot skillet, ensuring not to overcrowd the pan. Work in batches if necessary. Allow them to sear undisturbed for 4-5 minutes per side, until deeply golden brown and crispy.
Step 8: For the last minute of cooking, if desired, add the vegan butter to the pan. Baste the Lion's Mane Mushroom Steak pieces with the melted butter for extra richness and flavor.
Step 9: Remove the Lion's Mane Mushroom Steak from the pan and let them rest on a cutting board for a minute. This helps them retain their juices and tenderness.
Step 10: Garnish with fresh chopped parsley and serve immediately. Enjoy your delicious plant-based Lion's Mane Mushroom Steak!