Set a medium saucepan over medium-high heat and melt 1 tablespoon of butter. Add the onion and cook for about 2 minutes until softened. Stir in the uncooked long grain rice and garlic, cooking for another 2 minutes until the rice is lightly toasted and fragrant.

Pour in the chicken-style broth and bring to a boil. Reduce the heat to low, cover, and simmer for about 20 minutes until the rice is fully cooked. Once done, remove from heat and let it rest, covered, for 10 minutes to allow the rice to firm up and absorb any remaining liquid.

Gently fold in the remaining 2 tablespoons of butter, shredded zucchini, Parmesan cheese, thyme, and black pepper. Adjust seasoning to taste and serve warm.