Italian Baked Eggs with Mozzarella and Prosciutto

I rediscovered The Talisman Italian Cookbook on my kitchen bookshelf a few days ago. It is a classic Italian cookbook; full of simple, gorgeous recipes. Many of the recipes are not obviously Italian (read: tomatoes, oregano, olive oil, etc), but all sound like something an Italian Nonna would prepare for her grandchildren. 
I have yet to get past the section on 'eggs', which inspired this recipe. This takes 'baked eggs' to new gastronomic heights and made a tasty, simple supper.

Extra virgin olive oil or butter
1 Pound cooked potatoes-- cube shape work best, but slices are fine (good for using up left-overs)
1 Ball fresh mozzarella, buffalo or cow's milk
4 Thin slices prosciutto (optional)
4 Large, fresh eggs
1-2 tablespoons grated Parmesan
Salt and pepper

1) Preheat the oven to 200C (400F). Grease a small, shallow baking dish with olive oil or butter and layer in the potatoes- season with salt and pepper. Shred the mozzarella by hand and scatter over the potatoes. Wrap each prosciutto piece into a small nest shape and place equal distance apart in the baking dish (if not using prosciutto, make slight indents in the potatoes.) Now crack the eggs into each 'nest', season with salt and pepper, and sprinkle over the Parmesan. Bake, uncovered for 15-20 minutes (15 will have runny yolks, 20 minutes will be hard cooked). Serve with Oven Roasted Tomato and Garlic Sauce.

Serves 2-4