Preheat oven to 180C.

For the topping, peel and chop the potato and boil in a saucepan for around 15 minutes or until soft. Drain and add to a bowl with the milk and desired seasonings. Use a whizz stick to puree and set aside.

For the filling, peel and chop all vegetables.

In a large saucepan, add the onion, garlic and tomato and saute with oil or water. When fragrant, add the vegetable stock, carrot, green beans, lentils and herbs. Simmer for 10 minutes or until vegetables have cooked through.

Optional: In a small bowl, mix the flour and water until smooth. Add to the saucepan and quickly stir. Add salt and pepper to taste.

Pour lentil mixture into a casserole dish(es). Spread the sweet potato on top as desired.

Bake for 10 minutes or until the top of the potato has turned golden brown.

Remove and let cool for 5 minutes. Enjoy!