Preheat your oven to 375°F (190°C), placing the rack in the center.

In a large sauté pan over medium heat, add olive oil and cook the sliced potatoes for about 10 minutes until golden and tender.

Stir in chopped onion and minced garlic, sautéing for 3-4 minutes until translucent.

In a bowl, whisk together eggs, milk, salt, and pepper until smooth and pale yellow.

Spread the potato mixture evenly in the sauté pan and pour the egg mixture over it.

Sprinkle chopped spinach and parmesan cheese over the top.

Cook on the stovetop for 4-5 minutes until edges start to set.

Transfer the sauté pan to the oven and bake for 15-20 minutes until golden.

Let cool for a few minutes before slicing and serve warm.