We butter a 9-inch glass pie pan and spread the spaghetti on the bottom of the pan. We then beat the eggs, milk, half the cheese, salt, and pepper in a medium bowl with a fork. We pour the egg mixture over the spaghetti in the pan. We do not smush the spaghetti down into the eggs, we leave some sticking out to get crispy. We mince two leaves of sage and sprinkle it over the pie. We then sprinkle the remaining cheese and some more freshly ground black pepper. We place the pie pan, uncovered, in the oven and cook for about 30 minutes. We want the eggs to be cooked through and the spaghetti crunchy.
We carefully take the pan out of the oven with a pot-holder and let rest for a few minutes. Meanwhile, we heat a little olive oil in a pan over medium heat and when hot we fry our remaining sage leaves until slightly browned on each side. This only takes about a minute. We drain them on paper towels. We then cut the pie into wedges and enjoy topped with the fried sage leaves.