Preheat your oven to 400°F (200°C) and grease a 9x13 baking dish with butter or cooking spray.

Cook gluten-free penne in a large pot of salted boiling water for 8-10 minutes until al dente. Drain and place in the prepared baking dish.

Melt 2 tablespoons of butter in a saucepan over medium heat, add minced garlic and cook until fragrant. Whisk in flour, then gradually stir in broth and cream until thickened.

Remove the sauce from heat, stir in Dijon mustard, brown sugar, vinegar, and shredded Swiss cheese until melted.

Layer cooked chicken over the pasta, then add chopped ham, and pour the cheese sauce over.

Mix panko, melted butter, and garlic powder in a bowl, then sprinkle over the casserole.

Bake uncovered for 15-20 minutes until topping is golden brown and edges are bubbly.

Let the casserole sit for about 5 minutes before serving.