Take your ceramic oven pan and begin to place the zucchini on the bottom to form the first layer of the parmigiana. Be sure to cover the whole bottom of the plate.
Using a silicon basting brush, baste the first layer of zucchini with the egg.
Add about 2 tablespoons of the tuna and onion cream on top and spread around evenly on the zucchini. Add some mozzarella on top to ensure even melting.
Add another layer of zucchini. This time place the zucchini going opposite from your first layer. Repeat the process of basting with egg and adding the tuna and mozzarella.
Repeat the layering process until you use all of your zucchini and tuna. For my recipe, I was able to do 4 layers of zucchini but this all depends on how big your pan is.
Place it in the oven and cook for 30 minutes.
When finished, remove it from the oven and let the parmigiana sit and rest for about 30 minutes to an hour prior to eating.
When it is ready to eat, cut the parmigiana into squares and plate it up. Buon Appetito!