In a large bowl, combine the pork shoulder, fatback, and pork liver with the milk, potato starch, eggs, and pistachios.

You should end up with about 3 kg of mixture.

Season with the salt, white pepper, garlic powder, quatre épices, and nutmeg.

Line two terrine molds with strips of fatback; if you don’t have bard, simply brush the molds with sunflower or peanut oil.

Shape the mixture into balls, then slap each one into the mold to expel any air pockets.

Pack the mixture firmly to the rim of the molds.

If you have caul fat, lay it over the top; otherwise, moisten the surface and smooth it down well.

Preheat the oven to 150 °C.

Place the terrines in a bain-marie and bake at 110 °C until the internal temperature reaches 72 °C.

Remove from the oven, let cool to room temperature, then refrigerate for 24 hours.

The next day, pour a thin layer of aspic over the terrine and garnish as desired.