Wash the kumala and dry well. Trim the ends. Rub the kumala with oil and place on a baking tray. Cook at 200oC for 45-50 minutes or until well cooked. Alternatively prick the kumara with a fork and microwave on high power for 15 minutes or until tender.
Slice a top off each kumala and scoop the flesh into a bowl.
Add the pineapple, ginger, spring onions and Corned Beef and mix gently with a fork to break up the corned beef and mix the ingredients lightly. Do not mash.
Re-fill each kumala with 1/4 of the mixture and return or place on the baking tray. Sprinkle each with a little grated cheese.
Cook at 200oC for 15 minutes until piping hot and golden.