Heat a medium saucepan over medium heat. Add the butter and melt. Add the diced onion and saute, stirring occasionally, until the onion is mostly tender, about 3 minutes.
Stir in the minced garlic and saute another 2 minutes to cook the garlic.
Stir in the rice. Toast the rice, stirring often, until some spots are lightly browned, about 3-5 minutes.
Stir in the vegetable broth, chunky hot salsa, and tomato sauce. Bring to a simmer, stirring.
Allow to simmer undisturbed, with the lid on, for 15 minutes, or until the rice is tender and has absorbed the liquid.
Fluff with a fork before serving with crumbled cotija cheese and cilantro.
