Fry the onion until golden, add the carrots and add all but a handful of thyme. Pour in the wine, 150ml water and the tomatoes, then sprinkle in the stock cubes and simmer for 10 minutes. Tip in the can of lentils, then cover and simmer for another 10 minutes.

Meanwhile, boil the sweet potatoes for 15 minutes until tender, drain well. Then mash with the butter and season to taste. Pile in the lentil mixture into a pie dish, spoon the mash on top then sprinkle over the cheese.

Heat oven to 170C fan. Cook for 20 minutes until golden and hot all the way through.