Sear and press the lions mane mushrooms in a lightly oiled pan over medium-high heat. Let them develop color on both sides and press to your desired thickness. Cook through and baste with vegan butter and fresh herbs (rosemary, sage, thyme) for about 3 minutes. Remove the mushrooms from heat and let them rest on the side.
Meanwhile, chop all chimichurri ingredients (olive oil, red wine vinegar, garlic cloves, red onion, fresh parsley, fresh cilantro, salt, pepper, red pepper flakes) and add them to a bowl, then mix and set aside.
Slice the large shallot thin, then toss the slices in the seasoned flour mix (chickpea flour, salt, pepper, garlic powder, paprika). Fry the shallots over medium heat for about 1-2 minutes until they are golden and crispy. Assemble the sandwich with the cooked lions mane, chimichurri, crispy shallots, and arugula. Enjoy!
