Heat the olive oil in a large skillet over medium heat.
1 tablespoon olive oil
Once heated, add in the onion and a pinch of salt, and sauté for a few minutes until softened.
½ onion
Stir in the garlic, broccoli, and another pinch of salt.
2 garlic cloves, 4 cups broccoli florets
Cook for 4-5 minutes until the broccoli is tender. Stir in the chicken.
4 cups cooked chicken breast
Preheat the oven to 375℉.
In a saucepan, melt 3 tablespoons of butter over medium heat. Then, whisk in the flour until smooth. Slowly add in the chicken broth and milk while whisking until the mixture is smooth and thickened.
5 tablespoons butter, ⅓ cup flour, 1½ cups chicken broth, ½ cup whole milk
Stir in the sour cream, ½ cup cheddar cheese, poultry seasoning, salt, pepper, onion and garlic powder.
½ cup sour cream, 1½ cups shredded cheddar cheese, ¼ teaspoon poultry seasoning, ½ teaspoon salt, ¼ teaspoon black pepper, ¼ teaspoon onion powder, ¼ teaspoon garlic powder
Add the sauce to the skillet with the chicken and broccoli and stir to combine.
Transfer the mixture to a greased casserole dish.
Melt the remaining 2 tablespoons of butter, and mix it with the panko breadcrumbs.
5 tablespoons butter, 1 cup Panko Breadcrumbs
Top the casserole with the remaining cheese and breadcrumbs.
Bake for 20 minutes until the top is golden brown and the casserole is bubbly.