Rinse the rice under cold water until mostly clear and drain well.Melt butter in a skillet and sauté the diced onion for 3–4 minutes.Add vermicelli or orzo and toast until golden.Stir in the rice and toast for 2–3 minutes.Pour in broth and add salt, pepper, and bay leaf. Bring to a boil.Reduce heat to low, cover, and simmer for 15–18 minutes.Rest covered for 10 minutes, then fluff and serve.