Wash the potatoes thoroughly, peel them, and cut them into medium-sized cubes.

Place the cubed potatoes in a pot, cover with water, add a pinch of salt, and bring to a boil. Cook for 5-7 minutes until soft but not mushy. Strain and let cool.

Finely chop the onion. Heat oil in a frying pan over medium heat and cook the onion until softened and translucent.

Add the washed and chopped spinach to the pan with the onion and cook for 3-4 minutes until wilted. Remove from heat and let cool.

In a large bowl, whisk together the eggs, sour cream, salt, pepper, garlic powder, and baking powder.

Grate half of the cheese and fold it into the egg mixture.

Grease a baking dish with cooking spray or oil. Layer the cooled potatoes in the dish, followed by the spinach and onion mixture.

Pour the egg and cheese mixture over the top and sprinkle the remaining cheese on top.

Preheat the oven to 180°C (350°F) and bake for about 20 minutes or until the top is golden and bubbly.

Let the bake cool for a few minutes before slicing. Serve hot directly from the dish.