In a large saucepan heat oil over medium heat. Once hot, add the onion, garlic, carrot, celery, and all the spices. Stir and sauté until the vegetables are becoming golden brown.
Add the cornflour, tomato puree, worchester sauce, soy sauce, balsamic vinegar, and stir.
Next, add the cooked green or brown lentils, wine and stock. Bring to a boil, and then allow the mixture to simmer for between 10 minutes, or until slightly reduced and thickened.
Preheat the oven to 200C/390F
Spoon the lentil mixture into the baking dish.
Sprinkle on the frozen peas and top with the mashed potato carrot layer, spreading it with to cover the top of the pie.
Use a fork to create a pattern on the top of the mashed potato and carrot topping. Sprinkle with mixed herbs.
Place the dish on a baking tray (to protect the bottom of your oven in case of any leaks). Bake in the oven for 30 minutes. If you want you can grill at the end until the top is golden brown.