Combine the ingredients: Add the parsley, pickled Fresno peppers, olive oil, red wine vinegar, garlic paste, oregano, and salt to a small bowl.

Mix: Stir until everything is evenly combined. Set the chimichurri aside while you prepare the mushrooms.

Shred the mushrooms: Hold each king oyster mushroom firmly by the cap. Drag the tines of a fork down the length of the thick stem to create thin, meat-like shreds. Rotate the mushroom and continue shredding on all sides. Pull apart any thicker pieces with your fingers.

Make the seasoning mixture: Stir together the vegetable bouillon paste and water until combined.

Season the mushrooms: Add the shredded mushrooms to a bowl with the bouillon mixture, Cajun seasoning, liquid smoke, and optional soy sauce. Toss until the mushrooms are evenly coated.

Cook the mushrooms: Heat 2 tablespoons of oil in a large skillet over medium-high heat. Add the seasoned mushrooms and spread them into an even layer.

Brown until crispy: Cook for approximately 10 minutes, stirring only occasionally, until the moisture has evaporated and the mushrooms are golden brown and crispy around the edges. Transfer the mushroom filling to a plate, leaving any remaining seasoned oil in the skillet.

Add the tortillas: Reduce the heat to medium. Place the tortillas in the same skillet, working in batches as needed.

Add the fillings: Sprinkle cheese over one half of each tortilla. Top with the crispy mushroom filling and a small spoonful of chimichurri.

Fold the tacos: Fold each tortilla over the filling and gently press it closed with a spatula.

Cook until crispy: Cook for 2 to 3 minutes per side, or until the tortillas are golden and crispy and the cheese has melted.

Serve: Serve the mushroom tacos immediately with additional chimichurri on the side.