Ingredients

  • 1/4 cup butter
  • 6 yellow onions, halved and sliced 1/2 inch thick
  • 1/2 cup beef broth
  • 1/2 cup heavy cream
  • 2 tablespoons all-purpose flour
  • 1/4 teaspoon salt
  • 1/8 teaspoon pepper
  • 1/2 cup shredded Swiss cheese
  • 1/2 cup grated Parmesan cheese

Method

  • Preheat the oven to 350 degrees F (175 degrees C). Grease an 8 inch square baking dish.
  • Melt the butter in a large skillet over medium heat. Add onions; cook and stir until tender, about 5 minutes. Transfer to the prepared baking dish. In a medium bowl, stir together the beef broth and flour until smooth. Mix in the cream and season with salt and pepper; pour over the onions. Sprinkle Swiss cheese and Parmesan cheese over the top.
  • Bake for 25 to 30 minutes in the preheated oven, until cheese is golden brown and the sauce is bubbly.