Place the 500 g potatoes in the large pot and cover them with salted water.

Boil the potatoes until fork-tender, about 20 minutes, then drain them.

Mash the cooked potatoes until no large lumps remain.

Add 30 g butter and 50 ml whole milk to the mashed potatoes.

Season the mash with salt and black pepper, then stir until smooth and creamy.

Cook the 400 g fresh pork sausage in the frying pan without oil until browned.

Transfer the browned sausage to a plate and let it cool slightly.

Combine 300 g plain flour and 1 tsp instant baking powder in the mixing bowl.

Add 100 g cold butter and the egg to the flour mixture.

Add salt and black pepper, then rub the mixture quickly with your hands into coarse crumbs.

Line the baking pan with parchment paper and preheat the oven to 180°C / 356°F.

Scatter half of the crumb mixture into the lined baking pan and press it lightly into a base.

Spread the mashed potato mixture evenly over the crumb base.

Scatter the browned sausage over the potato layer and top it with sliced scamorza cheese.

Cover the filling with the remaining crumb mixture without pressing it down.

Bake at 180°C / 356°F until golden and crisp, about 30 to 35 minutes.

Rest the pie for 10 minutes, then cut it into 6 portions.