These are great! I don't know how this works, but even my co-workers and family said they taste just like bacon:

1 pack of Shiitake mushrooms
1 tsp. sea salt
1/4 cup olive oil

Wash, stem and cut Shiitakes into pieces. Place in bowl. Toss with sea salt and olive oil then spread out on a cookie sheet.
Bake at 300 for 1 hour, turning every 15 minutes. Be careful not to overcook!

I have also used dried Shiitakes and they work well. You just have to reconstitute them before you roast them. BTW --no other type of mushrooms will work.