Prepare the Rice: In a medium saucepan, melt the butter over medium heat. Add the diced onions and garlic, and sauté until softened and fragrant.
Combine Ingredients: Stir in the uncooked rice, beef broth, and French onion soup. Mix well.
Cook the Rice: Bring the mixture to a boil, then reduce the heat to low. Cover the saucepan and simmer for about 18-20 minutes, or until the rice is tender and the liquid is absorbed.
Add Cheese (Optional): If using cheese, sprinkle the shredded Swiss and Parmesan cheese over the top of the cooked rice. Cover the saucepan for a few minutes to allow the cheese to melt.
Serve: Garnish with fresh parsley if desired, and serve warm.