If the sausages you have purchased are not precooked, place in a large pan, add cold water to cover, and bring to a low boil. Lower the heat to a simmer and cook until cooked through, 1 1/2 to 2 hours, or according to package instructions. Drain and allow to cool.
6 Large Eggs yolks 1/2 cup Sweet Marsala 1 tablespoon Regular Balsamic Vinegar
In a large heatproof bowl, whisk the egg yolks, Marsala, and regular balsamic vinegar until foamy. Place the bowl over a saucepan of aggressively simmering water (the bottom of the bowl should not touch the water) and continue whisking with a passion until the custard is thick and "ribboning" like zabaglione. Remove from heat and continue whisking until cool.
6 Large Eggs whites 3 tablespoons Extra Virgin Olive Oil 1/2 cup Parmigiano Reggiano (freshly grated)
Slice the sausage into 3/4-inch-thick pieces. In a 10- to 12-inch nonstick saute pan, heat the olive oil until just smoking. In a shallow dish whisk the 6 egg whites. Working in batches, drip the sausage in egg whites and then dredge the sausage slices in the grated Parmigiano, carefully place in the pan, and cook until lightly crusty and golden brown on the bottom. Turn and repeat on the second side, then drain on paper towels.
Freshly ground Black Pepper 2 tablespoons Parmigiano Reggiano
Arrage the sausage on plates, spoon about 2 tablespoons of the custard sauce over each serving. Sprinkle with reserved Parmigiano-Reggiano and freshly ground pepper.