Panko is the Japanese word for bread crumbs.
There are many characteristics of Panko that often make them superior to American-style bread crumbs in many culinary applications.
You can generally find one or two types of Panko bread crumbs sold in stores. White Panko is made without the bread crusts and tan Panko is made using the whole bread loaf, crusts and all.
What differentiates Panko apart from regular bread crumbs is the processing.
The bread is processed in such a way that the resulting Panko (either white or tan) looks like flakes rather than crumbs. The flakey shape gives a much broader surface area than regular breadcrumbs. What this means for your homemade macaroni and cheese or macaroni casserole are crunchier toppings then using regular bread crumbs.
By itself, Panko has almost no flavor. This makes it the perfect blank canvas. Panko readily soaks up other flavors both from the seasonings in the food and also from whatever herbs and spices that you toss with it. A simple topping of Panko, a little salt and pepper, and some melted butter will give you a delightfully crunchy topping after baking.
Panko makes a wonderful crisp topping for casseroles. Toss Panko together with some grated parmesan, salt, pepper and maybe some herbs. Then, drizzle in some melted butter. Spread this topping liberally on a casserole, and upon baking, you will be rewarded with a light, crunchy and flavorful topping. This crunchy topping provides a nice contrast to your homemade macaroni and cheese or creamy macaroni casserole.
Try this technique on your next homemade macaroni and cheese recipe.
BUT WAIT: You do not have any Panko bread crumbs on hand.
You can substitute 2 cups of seasoned breadcrumbs for 1 cup of Panko.
Use a rolling pin to crush the croutons down. Be careful not crush them too finely or what you will have are seasoned bread crumbs. These will work but not as well as the larger less reduced in size crumbs resembling Panko.