Melt the butter in a pot or casserole dish. Add the diced yellow onion. Cook the onion on low-medium heat, until the onions begin to soften.
Add the rice and cook for an additional 1 to 2 minutes, stirring with a wooden spoon.
Pour in the chicken stock. Bring to a boil.
Lower the heat to low-medium and add the salt and pepper. Cook for 20 to 22 minutes or until done.