In a large skillet or saucepan, heat the olive oil over medium heat. Add the sliced onions and cook, stirring occasionally, until they soften and start to caramelize, about 15 minutes. This step reminds me of helping my abuela in the kitchen, watching her patiently coax the sweetness out of onions with care.
Add the butter to the onions and let it melt completely, allowing it to mix with the onions for an additional minute.
Stir in the rice, ensuring each grain is coated with the buttery onion mixture. Toast the rice for about 2 minutes, until it becomes lightly golden and fragrant.
Pour in the beef broth, then add the thyme, salt, and pepper. Stir well to combine all ingredients.
Bring the mixture to a gentle boil, then reduce the heat to low. Cover the skillet with a lid and let it simmer for 18-20 minutes, or until the rice is tender and has absorbed all the liquid. The aroma that wafts through the house at this point is nothing short of magical, reminiscent of the cozy evenings spent with family.
Once cooked, remove from heat and let the rice sit, covered, for 5 minutes. Fluff with a fork before serving.
