Slice onion toss with oil and 1/8 teaspoon of salt. Wrap in aluminum foil and put into pre heated cooker.
After 1 hour cut mushrooms in half length wise and add to cooker.
After 1 hour remove mushrooms shred and place into a casserole dish.
Remove onions and add to dish.
Add 1 cup vegan BBQ sauce and mix. Taste and if needed add salt and pepper.
Place casserole dish (uncovered) with mushrooms and sauce into cooker for 1 hour.