Preheat oven at 325°

In a large oven proof pot, cook spaghetti according to package directions, drain

Coat same pot with the butter. Place spaghetti back into the pot.

Cover the spaghetti with one of the cans of sauce. Add half the Swiss, half the pepperoni and half the mozzarella. Sprinkle with the oregano.

Now add the second can of sauce and repeat all layers (swiss, pepperoni and mozzarella)

Place in oven for approximately 25 minutes or until cheese is melted