Step 1: Heat the Oven
Set your oven to 350°F (175°C) and lightly grease a 9×13-inch baking pan.
Step 2: Prepare the Sauce Mixture
In a large mixing bowl, stir together the cream of chicken soup, sour cream, mayonnaise, garlic powder, onion powder, salt, and pepper until smooth.
Step 3: Add the Main Ingredients
Mix in the cooked chicken, frozen vegetable blend, and shredded cheddar cheese, making sure everything is well incorporated.
Step 4: Fill the Baking Dish
Spread the combined mixture evenly in the prepared casserole dish.
Step 5: Make the Crunchy Topping
In a smaller bowl, toss the crushed cornflakes (or fried onions) with the melted butter until fully coated.
Step 6: Bake the Casserole
Scatter the topping over the casserole and bake for 30–35 minutes, or until bubbly and nicely browned on top.
Step 7: Enjoy
Allow the casserole to cool for a few minutes before serving.
