Step 1

Preheat oven to 400ºF. On a large baking sheet mix together sliced potatoes, onions, and olive oil. Arrange potatoes in a single layer potatoes and season with salt and pepper.

Step 2

Roast for 20 minutes, flipping potatoes halfway through. Remove from oven when potatoes are golden brown. Turn down the oven to 375ºF. Set potatoes aside to cool slightly.

Step 3

When the potatoes and onions are cool enough to handle, arrange them in a greased pie plate (see pic in post). Spread half the potatoes and all the onions on the bottom of the pie plate. Arrange remaining potatoes, standing up and overlapping, around the edge to form a "potato crust."

Step 4

Whisk together the eggs, ricotta, parmesan cheese, 1/4 teaspoon salt, and 1/8 teaspoon pepper until smooth. Gently pour over potatoes and onions. If desired, drizzle additional olive oil on top.

Step 5

Put frittata back into 375ºF oven for 30 minutes or until middle is set and eggs are cooked through. If crust is becoming overly browned before eggs are cooked, use a  pie shield or loosely tent foil around crust. Serve hot or at room temperature.