What four toppings are on the Pizza Toppings Mount Rushmore?

Leonhart4 posted...

I don't know how extra cheese counts as a topping

I mean if it does then it's top 4 but it feels like cheating to include it

A topping is something that goes on top of the cheese

If there's a layer of cheese is put on, and then a second layer of cheese is put on, then that cheese is on top of the first cheese