In A Large Skillet, Cook Potatoes And Onion In Butter Until Tender And Lightly Browned. In A Bowl, Beat Eggs, Milk, Italian Seasoning, Salt And Pepper. Pour Over Potato Mixture. Sprinkle With Pepperoni. Cover And Cook On Medium-Low Heat For 10-12 Minutes Or Until Eggs Are Set. Remove From The Heat. Sprinkle With Cheese; Cover And Let Stand For 2 Minutes. Cut Into Wedges.