Preheat the oven to 350˚F. Cook the elbow macaroni according to the instructions on the package, drain and set aside.
Melt 2 tablespoons of butter in a saucepan over medium-low heat. Whisk in the flour and cook while stirring for 2 minutes. Gradually whisk in the milk and add the salt.
Whisk in seasonings if desired. We used garlic powder, ground mustard, black pepper, and onion powder.
Bring the mixture to a simmer over medium-low heat, stirring often.
Add the processed American cheese and stir until melted.
Remove from heat and stir in the shredded cheddar cheese.
Add the cooked elbow macaroni and stir to coat. Spread in a greased 11x7-inch (2.5-quart) casserole dish.
Mix together the panko breadcrumbs and melted butter. Sprinkle over the mac and cheese.
Bake at 350˚F for 20-25 minutes, until bubbly and golden brown.
Video
Notes
Store in an airtight container in the refrigerator for up to three to five days or in the freezer for one to two months. Thaw frozen macaroni and cheese in the refrigerator. Reheat it in the microwave or oven. You can add a little additional milk if necessary.