When the crust has finished par-baking, remove from the oven and increase the oven temperature to 375 degrees F.
Carefully remove the foil lining and pour the sugar in a suitable container to cool.
Arrange the bacon, onions, and diced ham evenly over the bottom of the baked crust.
Layer the cheeses evenly over the ham.
In a large bowl, whisk the eggs, yolks, and half and half, salt, pepper, and nutmeg until well combined.
Pour the custard into the prepared crust.