Preheat the Oven: Preheat your oven to 350°F (175°C).

Prepare the Carrots: In a medium saucepan, add sliced carrots and cover them with water. Bring to a boil, then reduce heat and simmer for 5-7 minutes, or until the carrots are slightly tender. Drain and set aside.

Make the Panko Topping: In a small skillet, melt 3 tablespoons of butter over medium heat. Add the panko bread crumbs, stirring until they are golden brown. Set aside.

Prepare the Cheese Sauce: In a medium saucepan, melt the remaining 4 tablespoons of butter over medium heat. Whisk in the flour to create a roux, cooking for 1-2 minutes until the mixture is slightly golden. Gradually pour in the half and half, whisking continuously until the sauce thickens.

Season the Sauce: Add the salt, black pepper, onion powder, coriander, and dry mustard to the sauce, stirring well. Lower the heat to a simmer and stir in the shredded cheddar cheese, allowing it to melt fully and create a smooth, creamy sauce.

Assemble the Casserole: In a baking dish, layer the cooked carrots. Pour the cheese sauce over the carrots, ensuring they’re evenly coated. Top with a generous sprinkle of toasted panko breadcrumbs.

Bake: Place the casserole in the preheated oven and bake for 20-25 minutes, or until the sauce is bubbly and the topping is golden brown.

Serve: Serve warm, and enjoy as a rich and flavorful side dish!