Mushroom and chicken vol-au-vents

Name: Mushroom and chicken vol-au-vents
Prep time: 30 min
Cook time: 1 h 40 min
Total time: 1 h 40 min
Yield: 20 pieces
Ingredients: 730 g homemade puff pastry; 50 g cheddar cheese; 100 g fresh Swiss brown mushrooms; 30 g onion; 20 g white wine; 25 g salted butter; ¼ tsp ground black pepper; 200 g full cream milk; 50 g water; 1 tbsp Chicken stock paste; 30 g plain flour; 150 g chicken breast fillet; 1 egg yolk; 1 spring onion/green onion; 2 sprigs fresh parsley