Preheat oven to 425 degrees. Lightly grease a 9-inch round glass pie pan and set aside.

In a medium bowl, combine potatoes, butter, Essence, and 1/8 tsp. salt and toss to combine. Add the Parmesan and toss to combine. Press the potato mixture into the prepared pan, spreading with your fingertips to evenly cover the bottom and up the sides. Bake until the potatoes are set and golden brown about 22 to 25 minutes.

Remove from the oven and let cool on a wire rack. Reduce the oven temperature to 350 degrees.

In a medium bowl, beat the eggs. Add the half-and-half, remaining 1/2 tsp. salt and pepper and whisk to combine. Add the Swiss cheese and ham, stir, and pour into the prepared potato crust. Bake until the center of the custard is set but still slightly soft, puffed and golden brown about 30 minutes. Transfer to a wire rack and let cool for 20 minutes before serving. Slice and serve. Makes 6 to 8 servings.