4x6 - Guy's Grocery Games

Chefs find that making your best dish using only ingredients that begin with the letter M isn't as easy as ABC. Next, they have to lighten up and make a grilled salad with only 6 pounds of ingredients. Then, the finalists have to make a signature burger with an ingredient from every aisle. Which burger will secure a chef's chance to bag up to $20,000 in the Triple G Shopping Spree?