Complex sentence: Thinly sliced pepperoni is a popular pizza topping in American-style pizzerias, a filling in the West Virginia pepperoni roll, and is used to make some varieties of submarine sandwiches.
Split into simpler sentences: Thinly sliced pepperoni is a popular pizza topping in American-style pizzerias and is used as filling in the West Virginia pepperoni roll. It is also used to make some varieties of submarine sandwiches.