Ingredients
Method
- Melt butter in a large pot over medium-low heat; slowly cook onions 25 to 30 minutes, until deeply caramelized and sweet.
- Add broth; bring to a simmer.
- Add tortellini; cook 5 minutes.
- Ladle into oven-safe bowls; top with Gruyere and broil 2 minutes, until bubbly and golden.