Preheat the oven to gas mark 4 / 180*C / 350F.
Chop up 6 large mushrooms, 1 large red onion and 3 cloves of garlic.
Open up a Bakewell medium sized oven bag and place the chopped vegetables inside.
Also add to the bag: salt, pepper, 1 teaspoon of lemon zest, 1 tablespoon of olive oil and 1 tablespoon of roasted pine nuts.
Tie the bag loosely with one of the ties provided.
Place the bag in an oven proof dish in the middle of the oven (making sure the bag does not touch the sides or heating element in the oven).
Cook for 20-25 minutes or until vegetables are cooked to your liking.
Carefully cut open the bag and serve.
Garnish with parsley and feta cheese.