Caramelize the onions: In a large skillet, heat olive oil over medium-low heat. Add sliced onions and cook, stirring occasionally until deep golden brown and caramelized, about 25-30 minutes.

Prepare gnocchi: While the onions are caramelizing, cook the potato gnocchi according to package instructions in boiling salted water until they float. Drain and set aside.

Combine: Gently add the cooked gnocchi to the skillet with caramelized onions. Pour in the beef broth and mix well. Let it simmer for a few minutes.

Broil: Transfer the mixture to a baking dish, top with shredded Gruyère cheese, and broil on high until bubbly and golden brown, about 3-5 minutes.