Preheat oven to 375°F (190°C). Lightly grease a 2-quart baking dish.

Cook gnocchi according to package directions. Drain and set aside.

In a large skillet, melt butter over medium heat. Add onions and salt. Cook for 25-30 minutes, stirring every 5 minutes, until onions are deeply caramelized.

Add garlic and cook for 1 minute.

Sprinkle flour over the onions and stir to combine. Cook for 1 minute.

Gradually whisk in beef broth and wine. Bring to a simmer and cook until thickened, about 3-5 minutes.

Remove from heat and let cool for 2-3 minutes. Stir in thyme, Greek yogurt, cooked gnocchi, shredded chicken, and 1 cup of the Gruyère cheese.

Transfer mixture to the prepared baking dish. Top with remaining 1/2 cup Gruyère and all the Parmesan cheese.

Bake for 20-25 minutes, until bubbly and golden on top.

Let rest for 5 minutes before serving. Garnish with fresh parsley.