In large saute pan, heat 3/4 cup olive oil. Cook half potatoes until tender and golden, turning often. Drain. Season with salt and pepper, to taste. Repeat with remaining potatoes.

Add 4 tablespoons olive oil to pan. Cook onions until soft, about 15 minutes. Add potatoes to onions.

In large bowl, beat eggs. Add eggs to potato and onion mixture. Stir in diced ham or prosciutto. Reduce heat to low and cook 8-10 minutes until golden brown on bottom. Invert platter on pan and flip omelet onto plate. Add remaining olive oil to pan; slide omelet back into pan.

Cook until golden brown on bottom.

Slide omelet onto serving plate. Let cool. Cut into wedges.