Step 1

Pre-heat the oven to 180ºC.

Step 2

Spray a large saucepan with low calorie cooking spray and over a medium heat, sauté the onions, carrots, celery and mushrooms for 10 minutes, until they begin to soften.

Step 3

Add the mustard powder, garlic granules, thyme and tomato puree to the pan and stir well.

Step 4

Stir in the stock, balsamic vinegar and soy sauce and bring to a simmer. Allow to cook for 10 minutes, until the vegetables are just soft.

Step 5

Meanwhile place the sliced potatoes into a pan of cold salted water and bring to the boil, reduce the heat and simmer for 3-4 minutes. Drain.

Step 6

When the vegetables are just soft, stir in the lentils, and pour the mix into an oven proof dish.

Step 7

Arrange the par cooked, sliced potatoes on top, spray with low calorie cooking spray and sprinkle on a little salt and freshly ground black pepper to taste.

Step 8

Place in the oven for about 30 minutes, until the potatoes are crisp and golden, but soft on the inside.

Step 9

Serve with your choice of accompaniment.