Pierogie pizzas are quintessential Pittsburgh. The only requirement is that they need to have lots of butter! (Sometimes when my friends and I go out to get this pizza, we even order it with extra butter.)
You will need:
Pizza dough (I like Trader Joe's refrigerated pizza doughs)
Shredded Cheddar Cheese
7 small red potatoes
1/2 onion, thinly sliced
LOTS OF BUTTER!
First make the mashed potatoes by boiling in a pot full of water until fork tender, about 15 minutes. While the potatoes are cooking, caramelize the onions by cooking them over medium heat until golden brown in plenty of butter. Once the potatoes are done, drain them and then mash them with (again) plenty of butter. I like to keep the potato peels on but if you don't like them, peel them after boiling. Roll out the dough and spread the mashed potatoes thickly over the entire surface. Cover with the caramelized onions and then sprinkle the cheese on top. Dot the pizza with pats of butter to melt in the oven and make a crispy crust on top of the pizza.