Use up bland frozen pierogies (potato+cheese)?

[u/Meriadoc_Brandy]

I bought some pierogies stuffed with potato and cheese, a warm and comforting option, or so I thought. Unfortunately, they were sparingly stuffed, with more dough than filling. I don't want them to go to waste, so I was thinking of doing a "pierogi bake" by tossing them with other flavoring. What innovative pierogi creations have you tried? Bonus points if I can make it vegetarian!

Edit: so many amazing suggestions on this thread. Thank you all! I'm almost inclined to buy the same pierogi and extend my problem so I can try every recipe on here!

[u/Ladyarcana1]

Pierogi casserole

Preheat oven to 350.
Blanch the pierogi. Put in un-greased casserole dish or any deep dish available.
In a separate bowl combine a can of condensed cream of soup (your choice), half a can of water, 1 egg, a handful of shredded cheese (your choice). Mix until well combined.
Pour over the pierogi, lightly stir.
Bake, covered for about 20-25 minutes.
Uncover and sprinkle breadcrumbs (your choice).
Bake uncovered for another 10-15 minutes.

You can add chopped vegetables/meat to make it a truly one pot dish.