Melt 1/2 tablespoon butter in a large skillet over medium high heat. Add the bell pepper and the mushrooms and saute for 2-3 minutes, until tender. Sprinkle with a small pinch of salt and then remove the vegetables to a small bowl and set aside.
Add the remaining butter to the hot skillet and allow it to melt over medium heat. Add the rice and stir to coat. Let the rice cook, stirring frequently for about 2 minutes. Add the onions and garlic and saute for 2 more minutes, until the rice is lightly brown and the skillet is fragrant.
Add the chicken broth and bring to a boil. Reduce the heat to low and cover with a lid, making sure it continues to simmer. Simmer until the rice is tender and the liquid is absorbed, about 20 minutes. Taste and adjust the salt if needed. Remove from the heat, stir in the cooked vegetables and then fluff with a fork before serving. Enjoy!