This Savory Pierogi Casserole with Kielbasa is the ultimate comfort food dinner. Cheesy pierogi, smoky sausage, and caramelized onions bake together in one pan for a hearty, family-friendly meal that comes together in under an hour.
Do not thaw the pierogi before using. Using them frozen prevents them from becoming mushy and helps them hold their shape perfectly during baking. For a extra-golden top, broil for the last 1-2 minutes, but watch it closely!