Homemade Hash Brown Casserole

Name: Homemade Hash Brown Casserole
Ingredients: 2 pounds frozen southern style hash browns thawed; 4 tablespoons salted butter; 2 tablespoons flour; 1 1/2 cups low fat milk; 1 1/2 cups vegetable or chicken broth; 1 teaspoon ground nutmeg; 1 tablespoon garlic powder; 1/2 teaspoon kosher salt; 1/2 teaspoon fresh ground pepper; 1 vidalia onion diced; 3 garlic cloves minced; 2 cups grated sharp cheddar; 1/2 cup low fat greek yogurt; 1 1/2 cups cornflakes crushed; 3 tablespoons salted butter melted