In a large oven-safe skillet, melt 2 tablespoons of unsalted butter along with 1 tablespoon of olive oil over medium-low heat. Add 3 thinly sliced yellow onions and a pinch of salt, stirring occasionally for 30–40 minutes.

In the last minute of caramelizing, add 2 minced garlic cloves and 1 teaspoon of fresh thyme to the skillet. Season with salt and black pepper to taste.

Pour in 1 tablespoon of balsamic vinegar or a splash of the beef broth into the skillet. Scrape the bottom with a wooden spoon to release the flavorful browned bits.

Stir in 1 cup of uncooked dry orzo pasta and add 3 cups of low-sodium beef broth and 1 cup of heavy cream. Bring to a simmer and cook uncovered for 8–10 minutes.

Once the orzo reaches tenderness, stir in 1 cup of shredded Gruyère cheese and 1 cup of shredded mozzarella cheese until creamy and well combined.

Preheat your oven to 400°F (200°C). Sprinkle the remaining cheese mixture over the top of the orzo and bake for 10–15 minutes until bubbly and golden.

Remove from oven and let it cool for 5–10 minutes before serving. Garnish with chopped fresh parsley or chives to add color.