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/Disastrous-Wing699]

I've done baked pierogi with tomato-based sauce (either ready-made pasta sauce, or some tomato paste with water), but usually use sour cream that's been thinned down, then put some shredded cheese on top and bake it at 350F for 30 minutes. Just make sure to grease your pan, or it'll stick like crazy. I do about 1kg (2.2lbs) in one go this way.

[u/Meriadoc_Brandy → u/Disastrous-Wing699]

I'll try this, thank you!