Chop the onion and garlic finely.

In a pan, heat the olive oil and sauté the onion and garlic until golden brown.

Season with salt and pepper to taste.

Add the sliced ham to the pan and cook for a few minutes until heated through.

In a separate bowl, whisk together the eggs, milk, flour, and baking powder.

Add the onion, garlic, and ham mixture to the egg mixture and stir to combine.

Grease a baking dish with butter and pour the egg mixture into the dish.

Arrange the cheese slices on top of the mixture.

Bake in a preheated oven at 180°C (350°F) for 40-45 minutes or until the top is golden brown.

Remove from the oven and let cool for a few minutes before serving.

Slice and enjoy!