You can (and should) use canned mushroom soup mix.
We’ve all seen the recipes that replace what we know is the best part of a green bean casserole—the canned cream of mushroom soup—with “real” ingredients. Well, in our house the can is the real ingredient and we’re pretty happy about it. It binds the casserole together, gives it that killer mushroomy flavor, and is nostalgic AF. Permission granted!
2½ cups fresh green beans, trimmed and cut into 2-inch-long pieces (about 10 ounces)
2 (10-ounce) cans cream of mushroom soup
¾ cup half-and-half
1 teaspoon garlic powder
½ teaspoon kosher salt
½ teaspoon freshly ground black pepper
8 ounces ham, cubed
½ cup diced onions
2½ cups (9 ounces) shredded cheddar cheese
1 cup canned French fried onions, divided
Preheat the oven to 350°F. Bring the chicken broth to a boil in a small pot, add the green beans, and cook until tender-crisp, 5-6 minutes. Drain into a bowl and save the chicken broth for another use.
In a large bowl whisk together the mushroom soup, half-and-half, garlic powder, salt, and pepper. Stir in the cooked green beans, ham, onions, 2 cups of the cheddar and and ¾ cup of the fried onions.
Spray a 10-x-12-inch baking dish with cooking spray and add the mixture to the casserole. Sprinkle with the remaining ½ cup cheddar and bake until bubbly and crusty, 40 minutes, adding the remaining ¼ cup French fried onions during the last 10 minutes of baking. Remove from the oven, let sit for 5 minutes, and serve.