Pre-heat oven to 200°C. Wrap each potato in foil and bake for 15 minutes or until cooked through.
Place lentils, finely chopped carrot, diced celery and stock in a small saucepan and bring to the boil. Reduce heat, cover and cook for 10 minutes.
Scoop out flesh of potatoes leaving a hole for filing. Mix potato with lentil mixture and milk then return to potatoes. Sprinkle with cashews and serve with a green salad.