Preheat the oven to 350°F. Lightly grease a 13x9x2-inch baking pan.

In a large bowl, mix the condensed cream of chicken with herbs soup, sour cream, and shredded smoked cheddar cheese until well-blended.

Gently fold in the thawed hash browns and chicken, ensuring everything is well-coated.

Transfer the mixture into the prepared baking pan and spread it evenly.

If using optional toppings, combine the crushed croutons and melted butter in a small bowl, then sprinkle this over the casserole.

Bake for 40 to 50 minutes until heated through and bubbly, until golden brown.

Garnish with fresh thyme if desired before serving.