Melt butter and olive oil in a large skillet over medium-low heat, then add sliced onions and cook for 30–40 minutes until caramelized.

Add minced garlic and thyme during the last minute of cooking.

Deglaze the pan with balsamic vinegar or beef broth and let it simmer.

Stir in dry orzo and pour broth. Simmer until pasta is nearly tender.

Lower heat, stir in cream and half of the cheese until melted.

Preheat oven to 400°F (200°C), sprinkle remaining cheese on top, and bake for 10–15 minutes.

Let rest before serving, garnished with parsley or chives.