Preheat oven to 350. Place a silpat over a baking sheet, set aside.
Combine all of the ingredients except for the sliced shiitake into a shallow glass pyrex or bowl. Whisk to combine.
Add in the sliced shiitake, and stir gently to combine. Allow to marinate for 20 minutes to an hour.
Place the shiitake in a single layer onto the silpat. Bake for 10 minutes, flip, then bake for an additional 15 minutes*. Increase the heat to 375, then bake for 10 minutes more. Flip, then finish for 10 more minutes. Keep an eye on them towards the end to ensure they do not burn.
Remove from the oven and place on paper towels to drain. As they drain, the edges will become crispy. Serve immediately.
*Baking times will differ based on the thickness and type of shiitake you are using. After baking for 15-20 minutes, just keep an eye on them to prevent burning.
Recipe by Olives for Dinner at http://olivesfordinner.com/2013/03/shiitake-bacon.html