Cook the Potatoes: Peel and cut the potatoes into thin slices. Bring a pot of water with a pinch of salt to a boil, then add the potatoes. Cook for 10–12 minutes, or until they can be easily pierced with a fork. Drain and set them aside to cool.

Prepare the Spinach Mixture : Heat a drizzle of vegetable oil in a skillet over medium heat. Sauté the finely chopped onion until translucent. Stir in the chopped spinach and cook until it softens. Sprinkle with a little salt and garlic powder. Remove from heat and let it cool for a few minutes.

Prepare the Creamy Egg Mixture : In a mixing bowl, whisk together the eggs, cream cheese, baking powder, and a pinch of salt until smooth.

Prepare the Casserole: Preheat your oven to 350°F (180°C). Lightly grease a medium-sized baking dish with oil. Start by placing a layer of half the cooked potato slices at the bottom. Top with half of the sautéed spinach mixture. Repeat with another layer of potatoes and spinach. Finally, pour the creamy egg mixture evenly over the top, covering all the layers.

Top with Cheese: Evenly distribute the shredded mozzarella cheese over the entire surface of the casserole.

Bake the Casserole : Place the casserole in the preheated oven and bake for 25–30 minutes, or until the top is golden and bubbly.

Rest and Serve: Allow the casserole to sit for a few minutes to cool slightly. Cut into individual servings and enjoy!