No need to preheat oven.
Place leg of lamb, potatoes, pumpkin and carrots into the roasting bag and season with dry KNORR mixture. Close bag at end with blue tie supplied.
Very gently massage KNORR mixture into the lamb on a stable surface. Ensure dry mixture is spread evenly.
Place bag sideways in a cool oven dish, ensuring ingredients are evenly spaced.
Bake at 180°C for 1 Hour and 40 minutes on the lowest shelf in the oven. Ensure that the grill is off at all times. Keep enough room for the bag to expand (bag must not touch the sides of the oven).
Cut the bag open, carefully remove the leg of lamb and allow to rest on a chopping board for 5 minutes before slicing.
Transfer the sliced lamb together with the vegetables to a serving dish and spoon any of the leftover juices in the cooking bag over the meal.