Melt butter or olive oil in a large skillet over medium heat. Add finely chopped onion and cook for 3-4 minutes until soft and translucent. Stir in minced garlic and cook for another 30 seconds until fragrant.

Add sliced fresh mushrooms to the skillet and sauté for 6-8 minutes until they release their moisture and start browning.

Stir in rinsed long-grain white rice, ensuring each grain is coated in the buttery mixture. Toast the rice for 1-2 minutes.

Pour in low-sodium chicken or vegetable broth, followed by a sprinkle of salt, black pepper, and dried thyme if desired. Stir and bring to a gentle boil.

Once boiling, reduce the heat to low, cover the skillet tightly, and simmer for 15-18 minutes.

After cooking, remove from heat but keep covered for 5 minutes to enhance fluffiness. Fluff rice with a fork and garnish with chopped parsley.