Step 1

Preheat oven to 350° F. Lightly grease a 13x9-inch baking dish or large casserole dish with cooking spray and set aside.

Step 2

Place chopped potatoes in a large microwave-safe bowl. Microwave on high power for 2 minutes, then stir. Microwave 2 more minutes on high power, until the potatoes are just starting to get tender. Use oven mitts to remove the bowl from the microwave, as it will be very hot.

Step 3

Heat the 2 tablespoons butter and the 1 tablespoon olive oil in a large skillet over medium heat. Add the onion, carrots and potatoes to the pan and cook, stirring often, until tender when pierced with a fork, 8-10 minutes.

Step 4

Add the garlic and flour and cook, stirring, for 30 seconds.

Step 5

Then stir in the chicken broth and milk, followed by the Italian seasoning, salt and pepper. Cook, stirring, for 3-4 minutes, until the sauce thickens.

Step 6

Stir in the cooked chicken, frozen peas and shredded cheddar cheese.

Step 7

Transfer the casserole mixture to the greased baking dish.

Step 8

To make the topping: In a small bowl, stir together the Panko breadcrumbs, Parmesan cheese and paprika. Add the melted butter and stir until well combined. Sprinkle the topping evenly over the casserole in the baking dish.

Step 9

Cover casserole with foil and bake for 25 minutes. Then uncover and bake for 10 minutes more, or until casserole is hot and bubbly and topping is golden brown.