Heat butter in a large skillet over medium-high heat until it begins to bubble.
Add rice and stir frequently until it becomes golden brown in color, (about 3-5 minutes).
Add the chili powder, cumin, and oregano, and season with 1 teaspoon salt and ½ teaspoon pepper. Stir and cook over medium heat until the spices are incorporated into the rice and become fragrant (about 1-2 minutes).
Add onions and minced garlic and fry until translucent (about 2 minutes).
Add chicken broth and salsa, and if desired, adjust seasonings by adding more salt and pepper.
Stir in diced bell pepper.
Bring the mixture to a boil, cover it, and turn the heat down to a simmer. Cook rice according to package directions (usually about 15-20 minutes). Rice is ready when it is fluffy and tender.
Sprinkle with optional cilantro and serve.