Preheat the oven to 350°F and spray a 9 x 13 baking dish with cooking spray. Or, you can bake this casserole in  individual [6-8 oz] casseroles.
In a large mixing bowl, stir the filling ingredients together, reserving 1/2 of the shredded cheddar cheese for the top.
Pour into the baking dish.
Sprinkle the top with the remaining shredded cheese.
Toss the panko breadcrumbs with melted butter and sprinkle evenly on top.
Bake for 30-35 minutes until the topping is golden and the filling is bubbly around the edges.