In a saucepan, combine soup and milk and mix well to combine. Bring to a simmer.
In a bowl, combine French fried onions and pork panko.
Pour frozen green beans in a casserole dish, then pour hot soup/milk mixture over top. Add ⅓ of the onion/pork panko mixture. Stir to combine and spread evenly in the pan.
Top with remaining onion/pork panko mixture and spread to coat evenly.
Bake in a preheated Traeger Grill set to 350°. Cook for about 30 minutes, until bubbly and golden brown. Serve immediately with an amazingly-grilled main dish.
Keyword casserole, green bean casserole, green beans, mushroom soup, pork panko, side dish