Set your oven to 350°F. This gives you time to get everything ready while it heats up.
Pour your canned green beans into a colander and drain them well. Let them sit for a few minutes to get all the water out. If you're using fresh beans, cook them until soft, then drain.
In a big bowl, add two cans of cream of mushroom soup, one softened package of cream cheese, and about a tablespoon of butter. Mix until smooth. I like to use a fork to mash the cream cheese first, then stir everything together. If your cream cheese is still hard, microwave it for about 20 seconds to soften it up.
Add the drained green beans to the bowl with your sauce. Use a spoon or clean hands to gently mix everything together. Make sure all the beans are coated with the creamy mixture, but try not to smash them up. I like to fold them in gentle, like Brenda does.
Pour the mixture into your casserole dish and spread it out evenly. Use the back of a spoon to smooth the top. This helps it cook evenly.
Put the dish in the oven at 350°F. Bake for 25–30 minutes, or until hot and bubbly. You'll see the edges starting to bubble when it's ready.
Take the dish out of the oven carefully. Sprinkle fried onions over the top - use as many as you like. I usually cover the whole top. Put it back in the oven for 5 more minutes. The onions should turn golden and get crispy.
Let the casserole cool for a few minutes before you serve it. This lets the sauce thicken up a bit. Then scoop it out and enjoy!