1. Preheat oven to 350°F. Spray 9x13-inch glass baking dish with nonstick cooking spray.
2. Bring large pot of salted water to a boil, and add potato slices. Stir, return to a full boil and cook 1 minute. Turn off heat, and let sit undisturbed 10 minutes, or until slices are tender but still firm. Drain, and set aside to cool.
3. Mix olive oil and pesto, and pour over cooled potato slices; toss slices to coat. Mix ricotta, Parmesan cheese, eggs, salt, pepper and nutmeg.
4. Place half of potatoes in baking dish. Spread ricotta mixture evenly on top, and sprinkle with half of mozzarella. Top with remaining potatoes and mozzarella.
5. Bake 45 minutes. Let rest 10 minutes before cutting into serving portions.