Set a large skillet over medium heat and add the butter. When the butter is melted, add onions. Cook for 2-3 minutes, stirring frequently, until softened.
Stir uncooked rice into the skillet and cook for an additional 1 minute, until the rice is lightly golden brown.
Add the vegan chicken broth and salsa, stirring to incorporate the salsa.
Bring just to a boil, then reduce to low heat. Cover and simmer for 20 minutes, or until rice is cooked and liquid has been absorbed.
Remove from heat and let the rice sit, covered, for 10 minutes to firm up.
Fluff rice with a fork and serve hot.