03Place the chicken in a large pot and cover with water. Add 4 teaspoons salt and bring to a boil, then immediately reduce to a low simmer. Cook the chicken until the internal temperature on an instant read thermometer reads 160 degrees F, 15 to 20 minutes.04Remove and cool slightly, then slice the chicken into thin strips or shred, and place in the bottom of the prepared dish. Add the broccoli and sprinkle the Parmesan over the top.05Melt the butter in a medium saucepan set over medium heat. Add the flour and use a wooden spoon or whisk to stir until smooth and cooked, 4 to 5 minutes. Add the nutmeg, and cayenne. Slowly whisk in the milk, Cheddar, stock and wine. Bring to a boil, whisking often. Reduce to a simmer and cook until thickened and smooth, 5 to 8 minutes.06Pour the sauce over the broccoli and chicken and then top with the breadcrumb mixture and sprinkle the paprika over the top. Cover the dish with foil and bake 15 minutes. Remove the foil and bake until the top is golden and the casserole is bubbling, 15 minutes.07Cool for about 5 minutes and then serve.