Heat oil and fry pinion and garlic in a saucepan.

Add in potato, carrot and meat. Add the celery last.

Preheat oven to 180°C.

Season with chili and tomato sauce. Simmer until potato in soft.

In another bowl, mash the boiled potatoes with milk, fine salt, and butter to a smooth consistency.

Spread meat mixture in a ovenproof dish, then cover with mashed potatoes.

Brush top with butter. Bake in oven until top is golden-brown.