Melt 2 tablespoons of unsalted butter in a large skillet over medium heat. Add the sliced yellow onions and a pinch of salt, stir gently, and cook for 25-30 minutes until caramelized.

Push the onions to one side, add minced garlic, and sauté for 1 minute until fragrant.

Add 1 cup of Arborio rice to the skillet and stir vigorously for 2 minutes to toast slightly.

Pour in 4 cups of low-sodium chicken broth, bring to a boil, then reduce heat to low and cover. Let simmer for 15-20 minutes until the rice is tender.

Remove from heat and fold in the fresh thyme and grated Parmesan cheese. Adjust consistency with more broth if needed.

Serve immediately, garnished with extra thyme or herbs as desired.