Heat the butter and oil in a medium pot with a tight fitting lid over medium heat. Once its melted and hot, add the carrots, celery and onion with a large pinch of salt. Cook, stirring often, until everything has softened up...about 7-10 minutes. Then add the garlic and cook a minute or two more, until fragrant. Stir in the rice and seasonings and increase the heat to med-high.

Stir often, so the rice toasts evenly for about 3 or so minutes. Then stir in the broth and place on the lid. Once it starts to come to a low boil, which should be fairly quickly, decrease the heat to low and let simmer undisturbed for 13-15 minutes, or until the liquid has been absorbed. Then turn off the heat and keep the lid on an additional 5 minutes. Then fluff with a fork and serve.