Heat the sunflower oil in a large, heavy-based casserole dish over a moderate heat. Season and then sear the beef chunks, in batches if necessary, until golden brown in colour all over. Remove and transfer to a colander set over a bowl.
Reduce the heat a little then add the potato the dish and let it cook for 1-2 minutes, stirring occasionally. Add the lentils, chopped tomatoes, sun-dried tomatoes, bay leaf and beef back to the dish.
Stir well, then add the stock. Bring the stew to the boil, then cover and reduce to a simmer for 60-70 minutes until the beef is tender and the lentils are soft and cooked. Remove from the heat and adjust the seasoning to taste.
Spoon into individual ceramic serving dishes.
This recipe is perfect for making in large batches and freezing to use at a later date.
In order to enjoy optimum flavour and quality, frozen items are best used within 3 months of their freezing date.
Always defrost and heat thoroughly before eating. Never re-freeze food that has already been frozen; this includes raw and cooked ingredients such as meat, fish and poultry.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.