them mostly in one layer so they cook evenly.
Scatter the thinly sliced onion evenly over the frozen pierogi, tucking some slices down between them so every bite gets a little flavor.
Drizzle the melted butter evenly over the onions and pierogi. If you’re using sliced butter instead of melted, dot the slices all over the top so they can melt down as it cooks.
Cover the slow cooker with the lid and cook on LOW for 3 to 4 hours, or until
