Step 1 Preheat oven to 190°C. Spray a non-stick frying pan with oil and cook chicken over high heat for 2–3 minutes, or until golden brown. Remove, set aside.
Step 2 Lower heat to medium and spray pan with oil. Add onion, potato and carrot, cooking for 5–6 minutes, until onion is soft. Add garlic and mushrooms, cooking for another 2–3 minutes.
Step 3 Add wine and simmer until almost evaporated. Return chicken to pan, adding stock. Simmer for 5–6 minutes, until slightly reduced and chicken is just cooked through. Add cornflour mixture and simmer for a further 2 minutes, until slightly thickened. Remove from heat and stir in sour cream and mustard.
Step 4 Spoon mixture into 4 x 1-cup capacity ovenproof dishes. Spray each sheet of filo pastry lightly with oil, and stack on top of each other. Cut pastry into quarters and place on top of dish, scrunching pastry to fit into the dish. Spray with a bit more oil.
Step 5 Bake for 20 minutes, or until pastry is crisp and golden brown. Remove and set aside for 5 minutes before serving with a large green salad.