Prepare the eggs:
In a bowl, beat the eggs and season with salt and ground black pepper to taste. Set aside.
Cook the meat and vegetables:
Heat a little vegetable oil in a large frying pan over medium heat.
Add the finely chopped onion and minced garlic and sauté until soft and translucent.
Add the ground meat and cook until golden brown.
Add the sliced ​​mushrooms, season with salt and ground black pepper to taste and cook until the mushrooms are tender.
Add the tomato sauce and cook for another 2 to 3 minutes. Remove from the heat.
Assemble the casserole:
In a greased baking dish, arrange half of the cooked potato slices.
Spread the meat and mushroom mixture evenly over the potatoes.
Arrange the remaining potato slices on top.
Pour the beaten eggs over the entire dish.
Spread the grated mozzarella cheese evenly over the top.
Bake:
Bake in the preheated oven for 30 minutes or until the top is golden and the cheese is bubbling.