Heat a 10-inch skillet or saute pan over medium-high heat. Heat olive oil until shimmering, then add celery, carrots and onion. Saute for 2-3 minutes. Add mushrooms and pine nuts, if using.
Add 1 cup of rice to the pan and saute for 5 minutes, stirring frequently. As rice begins to brown, you can add another tablespoon of oil if it seems dry.
Pour in low sodium chicken broth and bring to a simmer over medium heat. Stir in ½ teaspoon salt. Cover, reduce heat to low and steam for 15 minutes.
Let the rice rest for 5-10 minutes, then fluff and serve.
Notes
This recipe can easily be doubled without adjust the cooking time.