White Sauce
Start by cutting the peeled potatoes into round slices.
Transfer all of them to a large saucepan, add enough water to cover them, add the salt and let them cook for 10 minutes.
Cut the Calabrese sausages into round slices.
Cut the onion into strips.
Once the potatoes have cooked through, drain all the water and set aside.
Next, in a skillet, add one drizzle of olive oil and fry the Calabrese sausages with the onion strips, stir-fry until golden brown.
Once you’ve done that, in a large saucepan over medium heat, add the unsalted butter and stir until melted, add the wheat flour and stir until incorporated. Gradually add the milk and keep stirring nonstop until a smooth and uniform creamy sauce forms.
Now, season it with the black pepper, the salt and the nutmeg, stir well. Add the light cream and stir until combined.
In a nice baking dish, add the white sauce until the bottom is fully covered, top it with a layer of the cooked potatoes, add the calabrese sausages and finally, top them with the rest of the white sauce.
Sprinkle the grated mozzarella cheese all over it.
Take to a preheated oven at 180°C (350°F) and bake for 40 minutes.
Serve.