01 -
Lightly grease the insert of the slow cooker to prevent sticking and ensure easier cleanup.
02 -
Arrange frozen beef meatballs evenly across the bottom of the slow cooker. Scatter sliced onions on top of the meatballs.
03 -
Pour both cans of condensed French onion soup over the meatballs and onions. Use a spoon to gently mix so the soup and onions coat all the meatballs.
04 -
Cover with the lid and cook on low for 4 hours or on high for 2 hours. Cook until onions are completely soft and meatballs are heated through.
05 -
Twenty minutes before serving, evenly sprinkle shredded Gruyere cheese over the meatballs. Re-cover and allow the cheese to melt.
06 -
Spoon meatballs, onions, and plenty of sauce over mashed potatoes, toasted bread, or rice. Serve hot.