Step 1

Heat oil in large saucepan, cook onion, carrot and celery, stirring, until softened and browned lightly. Add lamb, cook, breaking apart with the back of a wooden spoon, for about 5 minutes or until well browned. Add flour, cook, stirring, for 2 minutes. Gradually stir in stock, then sauces and peas. Simmer, uncovered, about 10 minutes or until sauce thickens.

Step 2

Meanwhile, place mashed potato in a medium microwave-safe bowl. Heat in microwave on HIGH (100%) for 2-3 minutes or until heated through; whisk until smooth.

Step 3

Preheat grill.

Step 4

Spoon lamb mixture into a 2.5 litre (10-cup) ovenproof dish. Spread potato over hot lamb mixture and sprinkle with cheese. Grill until the topping is browned lightly.