Tartra is a traditional dish originating from Piedmont. It consists of a baked savory custard that's infused with onions and herbs. Although there are many variations, it's usually made with a combination of heavy cream, milk, butter, onions, eggs, grated cheese, nutmeg, salt, pepper, sage, and rosemary.

The cream, milk, sage, and rosemary are mixed and left to chill in the fridge. The onions are cooked in butter, and mixed with beaten eggs, the cream mixture, cheese, nutmeg, salt, and pepper. The mixture is placed in buttered custard cups and baked in the oven until the tops become golden and the custard is set.

The custard is inverted onto a plate and served warm as an appetizer. Tartra was often served with bagna cauda due to its pungency that contrasts the tartra's richness.