Make macaroni and cheese according to package directions. Transfer to a medium-size baking dish or casserole dish.
Melt butter in a medium bowl on low power in the microwave. Add breadcrumbs to bowl and toss to combine with butter. Sprinkle breadcrumb mixture over top of macaroni and cheese. Place in oven and bake for 10 to 15 minutes, or until browned on top.