Heat oil in a non-stick pan, add garlic and fry lightly till golden.
Add onions and fry till light brown.
Mix in mince and fry till pale brown.
Stir in salt, chili powder, black pepper and 1 cup water, transfer to pressure cooker and cook under pressure for 10 minutes. Allow cooker to cool before opening it.
Stir in Worcestershire sauce and tomato sauce, and place in an ovenproof dish, about 8" in diameter.
Combine all ingredients for mashed potatoes and beat till fluffy.
Spread potato over mince or using a wide nozzle, pipe it over the mince, to cover completely.
Bake in an oven preheated to 180C (250F) for 20-25 minutes.
Serve with a green salad and hot crusty bread rolls.
Add 1 cup shelled green peas after adding mince and cook for a minute. Add 1/2 cup boiled macaroni and 2 sliced green capsicums after removing mince from cooker. You can even add a diced carrot and 100g sliced mushrooms with the green peas.