Preheat the oven to 200°C and line a baking sheet with a reusable baking mat or parchment paper.
If you are using banana peels, use a spoon to scoop out (and discard) any leftover flesh on the inside lining. Slice the banana peels into about four strips per peel or the oyster mushrooms into thin strips, around 3⁄8 inch thick.
Make the marinade: In a medium-sized dish, combine all the marinade ingredients and mix well. Submerge the banana peels or mushroom slices in the marinade and soak for 10 minutes to an hour, as you like.
Transfer the marinated peels or mushroom slices to the prepared baking sheet. Brush with more marinade to coat.
Bake for about 15 minutes, until crispy, flipping halfway through. Serve immediately.