Cook the sausages and potatoes together in boiling water until the potatoes are done. Drain.

Chop up the sausages into small pieces and put aside. Mash the potatoes in a separate bowl.

Add the butter, grated onion, milk, 2 tspn salt, and pepper to the potatoes and mix well.

Heat the oil in a skillet or pan on medium-high heat. Add the chopped onion and chili pepper and saute until soft.

Add the sausages, chopped tomatoes, and 1/2 tspn salt and continue cooking, stirring frequently. Add the 2 tbsp parsley, do a final stir and remove from heat.

Place an even layer of the mash potatoes on the bottom of a baking pan.

Pour the sausage mixture over the mash potatoes and top with an even layer of mozzarella.

Cover the mozzarella with a final layer of mash potatoes topped with the Parmesan and 1 tbsp parsley.

Bake for 30 minutes at 400 degrees Fahrenheit.