Preheat the oven to 350 ℉ degrees.
Clean and cut the ends of the green beans, then cut them into small pieces.
Bring a large pot of water to a boil. Carefully add the green beans to the water and cook for 5-7 minutes to desired sweetness. Keep in mind that they will soften slightly more when cooked.
Remove the green beans from the pot and place them in a bowl of ice water to stop cooking. Drain and set aside to let the beans dry while preparing the sauce.
In a large skillet, melt the butter over medium heat. Add the mushrooms and cook until softened. Add the garlic and cook for an additional 30 seconds.
Sprinkle with flour and stir to create a thick paste. Cook 2 to 3 minutes.
Stir in broth, half and half, salt and pepper and Worcestershire sauce. Bring to a boil and simmer for a few minutes, as the cooking will thicken.
Remove the sauce from the heat and add the Parmesan. Stir while the cheese melts in the sauce.
Add green beans to mushroom sauce, tossing to coat. Add 1/2 cup of fried onions and stir.
Pour the green bean mixture into a baking dish.
Bake at 350 ℉ for 20 minutes. Sprinkle the remaining fried onions on top and continue to set back for an additional 5 minutes until golden brown.
Serve hot and enjoy. yum!!