In a large cast iron skillet, melt the butter over medium high heat. Then add the diced onions and sauté until the onions are translucent. Then add in the minced garlic and cook for 1 minutes until the garlic is aromatic.
Then add in the green beans, cream of mushroom soup, milk, salt and pepper. Gently stir and cook until the green beans are heated through (2-3 minutes) and all the ingredients are combined.
Then stir in half of the French fried onions.
Then top the casserole with the remaining French fried onions.
Move the pan to the oven and then broil for 2-3 minutes to brown the top of the casserole (watch closely to make sure that the top does not burn). Remove the casserole from the oven, allow it to sit for 5-10 minutes and then it’s ready to serve and enjoy!
Notes
This casserole is best served fresh but you can refrigerate the leftovers in an airtight container for up to 5 days. I love making this recipe in a cast iron skillet so that the pan can go from the stovetop to the oven. If you do not have a cast iron skillet, this can be made in a regular skillet and just skip the broiling of the top of the casserole.