Broccoli, bacon and mushroom pie

Ingredients

• 2 tablespoons olive oil
• 2 rashers rindless bacon, diced
• 1 onion, finely chopped
• 1/3 bunch parsley, stalks and leaves finely chopped
• 3 cloves garlic, crushed
• 2 teaspoons rosemary leaves, chopped
• 350 grams button mushrooms, halved
• 2 tablespoons plain flour
• 1 cup chicken stock
• 1 cup milk
• 2 heads broccoli, stalks thinly sliced, cut into small florets
• 8 sheets filo pastry, halved
• 1/2 cup grated parmesan