In a medium mixing bowl, combine all of your ingredients except the mushrooms. Whisk to combine. Add the sliced mushrooms to the oil and seasonings. Toss gently to insure that each side of the mushroom slices is evenly coated. Marinate for 20 minutes to 1 hour.
Preheat oven to 350°F. Arrange marinated mushrooms in a single layer on a parchment paper-covered rimmed baking sheet.
Bake mushrooms for 10 minutes, then flip over the slices and bake an additional 15 minutes.
Increase the oven temperature to 375°F, bake another 10 minutes before flipping the mushroom slices and baking 15 minutes more. Note: for the last 15 minutes, you will need to keep an eye on the mushrooms to make sure that they don’t burn.
Remove baking sheet from oven and drain excess marinade by transferring mushroom slices to a paper towel. They will crisp up as the oil drains off.
If you are wanting more ‘smoke’ flavor, try adding 3/4 tsp of liquid smoke.
You can use AllSpice Dried Shiitake Mushrooms, but fresh mushrooms will give you a better texture in the end.