This butter is what will soak into the dough and keep everything tender.
Divide the buttered pierogi mixture evenly between the two sheets of foil, piling it into the center of each sheet. Bring the long sides of each foil sheet up and over the filling, then fold them together tightly several times to seal. Roll up the short ends firmly so you have 2 completely sealed foil packets with no big gaps for steam to escape.
Sealed foil packets filled with sausage and pierogies
Sealed foil packets filled with sausage and pierogies
Place the foil packets seam-side up into the slow cooker, stacking them slightly if needed so the lid can still close fully. Cover the slow cooker with the lid, making sure it fits snugly to trap in steam.
Cook on LOW for 4 to 5 hours, or on HIGH for 2 to 2 1/2 hours, until the pierogies are very tender and the sausage is heated through. The onions should be soft and almost jammy, and there will be buttery, savory juices pooled inside each packet.
Opened foil packet with tender pierogies and sausage inside
Opened foil packet with tender pierogies and sausage inside
Carefully open the slow cooker lid away from your face to avoid the steam. Using tongs or oven mitts, lift out one foil packet at a time and place it on a rimmed baking sheet or cutting board. Open each packet carefully—hot steam will escape—and gently stir the contents so the buttery juices coat everything and soak into the pierogi dough.
Serve the sausage and pierogies straight from the opened foil packets, spooning some of the buttery onion-sausage juices over each portion. If you like a little color, you can sprinkle on fresh chopped parsley or black pepper before serving, but it’s completely optional and not needed for the basic 4-ingredient version.
Served bowl of sausage and pierogies with buttery onions
Served bowl of sausage and pierogies with buttery onions
Variations & Tips
You can tweak this 4-ingredient base a few different ways while keeping the same foil-packet, slow cooker method. For extra flavor without adding more core ingredients, use a smoked kielbasa or a spicy andouille sausage to change the overall vibe. If you like a bit of tang, serve the finished packets with a spoonful of prepared sauerkraut or a dollop of sour cream on the side, added at the table so they don’t count toward the main ingredient list.
To lighten things up slightly, you can use turkey smoked sausage and replace half of the butter with low-sodium chicken broth; just keep at least a few tablespoons of butter so the pierogi dough still soaks up that rich flavor. For a crisper top, transfer the cooked contents of the foil packet to a broiler-safe dish and broil for 2–3 minutes to get some browned edges.
Broiled sausage and pierogies with browned edges in a baking dish
Broiled sausage and pierogies with browned edges in a baking dish
Food safety tips: Always keep the pierogies frozen until you’re ready to assemble, and don’t thaw them on the counter. Use fully cooked, ready-to-eat smoked sausage and keep it refrigerated until prep time. Make sure the foil packets are tightly sealed so the internal temperature stays hot and even; the mixture inside should reach at least 165°F before serving.
Refrigerate leftovers within 2 hours of cooking and reheat thoroughly before eating, discarding any leftovers that have been left at room temperature too long.
