Preheat your oven to 190°C (375°F) and grease a baking dish.
Place the grated potatoes in a clean kitchen towel and squeeze out excess moisture.
In a large bowl, whisk together the eggs, milk, melted butter, baking powder, salt, and black pepper.
Stir in the flour and mix until smooth.
Add the grated potatoes, crumbled bacon, cheddar cheese, Parmesan cheese, and chopped green onions (if using). Mix well.
Pour the mixture into the greased baking dish and spread evenly.
Bake for 30-35 minutes, or until the top is golden brown and crispy.
Let it cool for a few minutes before slicing. Serve warm and enjoy!