Mix hash browns, soup, sour cream, 1 stick melted butter, and onion in a large mixing bowl.
Pour into a buttered 9×13” glass casserole dish and smooth the top.
Sprinkle with salt, pepper, and parsley flakes.
Crush Ritz crackers and combine with 1 cup melted butter using a fork.
Spread cracker mixture evenly over the top of the casserole.
Bake uncovered at 350°F for 1 hour, until top is golden and bubbly.
