Preheat your oven to 375°F (190°C). Line a large baking sheet with parchment paper. While the oven heats you can slice the mushrooms, discarding the stems (see notes).
Add the soy sauce, olive oil, maple syrup, and liquid smoke to a medium bowl and mix. Add the sliced shiitake caps and gently toss to evenly coat.
Spread the shiitakes in a single layer evenly over the prepared baking sheet. Bake 25 - 30 minutes, stopping to stir a few times until they have reduced in sized and are a dark golden brown. Remove from the oven. They will get slightly crispy as they cool. Enjoy right away or store in an air-tight container in the fridge for up to 4 days.
