Man on the street Doc Willoughby visits Tony Maws at Craigie on Main to learn all about burgers from a pro. Then, host Christopher Kimball goes into the kitchen with test cook Bridget Lancaster to learn how to make the Best Grilled Burger at home. Then, test cook Dan Souza demonstrates why you should grind your own burger meat. Next, tasting expert Jack Bishop challenges Chris to a tasting of Swiss Cheese. And finally, test cook Dan Souza uncovers the secrets to making Thick-Cut Sweet Potato Fries.