Preheat oven to 375° F. Grease a 9x13 inch baking dish. Set aside.
Melt butter in a large saucepan over medium heat. Add garlic and saute for 30 seconds. Whisk in flour and stir constantly until combined and flour turns golden-brown; about 2 minutes.
Whisk in milk until combined then stir in chicken broth, sour cream, cream cheese, salt and pepper. Simmer 5 to 10 minutes or until cream cheese is melted all the way.
Add cooked chicken and poppy seeds to sauce mixture. Stir to combine then pour into prepared baking dish. Top with crushed crackers. Pour melted butter evenly over crackers.
Bake, uncovered, 15 minutes. Remove from oven and let stand 5 minutes before serving over cooked pasta. Garnish with chopped parsley. Enjoy!