Every time the old man visits, this is what he's after. He loves it, without a doubt!

1. Preheat your oven to 350°F (175°C).
2. In a large pot, bring salted water to a boil. Add the sliced potatoes and cook for about 10 minutes, until just tender. Drain and set aside.
3. In the same pot, blanch the green beans for about 3-4 minutes until they are just beginning to soften. Drain and set aside.
4. In a large mixing bowl, combine the diced onion, shredded cheddar cheese, sour cream, and cream of mushroom soup. Mix well.
5. Add the potatoes and green beans to the mixture. Season with garlic powder, salt, and pepper. Stir gently to combine.
6. Pour the mixture into a greased 9x13-inch baking dish. Spread it out evenly.
7. In a separate small bowl, mix the melted butter with the crushed cornflakes or breadcrumbs. Sprinkle evenly over the top of the casserole.
8. Bake in the preheated oven for 25-30 minutes, or until the top is golden brown and the casserole is bubbly.
9. Let the casserole rest for a few minutes before serving to allow the flavors to meld together.
Variations & Tips
For a bit of extra flavor, you can add cooked bacon bits or diced ham to the mixture. If you're a fan of spice, consider adding a pinch of cayenne pepper or some diced jalapeños. For a vegetarian option, substitute the cream of mushroom soup with a cream of celery or cream of asparagus soup. This dish is also a great way to use up leftover veggies from your garden - feel free to throw in some chopped carrots or bell peppers for added color and nutrition.