Preheat your oven to 350°F. Prepare the green beans by draining canned beans or blanching fresh beans in boiling water for 3-4 minutes, then plunge into ice water.
In a large mixing bowl, combine cream of mushroom soup, milk, soy sauce, and garlic powder. Stir until smooth.
Add the drained green beans to the creamy sauce and fold gently. Season with salt and pepper to taste.
Mix half of the French fried onions into the green bean mixture, then pour into a baking dish and top with remaining onions.
Bake for 25 minutes, stir gently, then bake for an additional 10-15 minutes until onions are golden brown and casserole is bubbly.