Prepare the Oven
Preheat oven to 375°F (190°C).
Lightly grease a 9×13-inch baking dish.
Make the Cream Sauce
Melt butter in a saucepan over medium heat.
Whisk in flour and cook for about 1 minute until lightly golden.
Gradually pour in warm milk while whisking constantly.
Simmer until thickened (about 3–5 minutes).
Stir in salt, pepper, Dijon mustard, mozzarella, and Parmesan.
Cook until smooth and creamy. Remove from heat.
Season the Chicken
In a bowl, mix shredded chicken with garlic powder, salt, and pepper.
Assemble the Lasagna
Layer in this order:
Thin layer of cream sauce
3 lasagna noodles
Half of the chicken
Half of the ham slices
1 cup Swiss cheese
Sauce
Repeat layers once more.
Finish with:
Final layer of noodles
Remaining sauce
1 cup mozzarella on top
Bake
Cover with foil and bake for 25 minutes.
Remove foil and bake an additional 15 minutes until golden and bubbling.
Rest Before Serving
Let sit for 10 minutes before slicing.
This helps the layers hold together.