Filo Pie with a White Bean, Leek, Mushroom, Thyme and White Wine Sauce Filling - Vegetarian Society

Ingredients

• 2 tbsp olive oil
• 1 medium onion, finely diced
• 1 leek, sliced
• 300g chestnut mushrooms, quartered
• 1 clove garlic, crushed
• 2 tsp dried thyme
• 100ml dry white wine
• 100ml vegetable stock, made with 1 low-salt vegetable stock cube
• 300ml skimmed milk
• 2 bay leaves
• 1½ tbsp cornflour
• 2 tbsp cold water
• 40g half-fat Cheddar cheese, grated
• 75g light soft cheese
• 2 tsp Dijon mustard
• 2 x 400g cans haricot beans, drained and rinsed
• 4 sheets filo pastry
• Black pepper, to taste
• 320g green beans, steamed or boiled