Slice the mushrooms into large slices, sprinkle with salt and pepper.
Then in a mixing bowl, whisk the apricot jam, soy sauce, rice wine vinegar, orange juice and zest, water and chili flakes. Whisk until all the jam has dissolved and there are no big chunks.
Now add the sliced mushrooms to the marinade. Stir to coat. Marinate for at least 20 minutes, the longer the better. Stirring every once in a while.
Then preheat oven to 425 degrees.
Now, place the sliced mushrooms onto a baking sheet lined with aluminum foil. Sprayed with non stick spray. Brush the mushrooms with more marinade, coating well. Then bake at 425 degrees for about 10 minutes or until they start to brown.
Now, flip the mushrooms, brush with more marinade, and bake for another 10-15 minutes or until the mushrooms are brown and sticky and juicy.
Remove from the oven, brush with remaining marinade. Serve immediately with rice, other veggies or whatever you like!