You will earn Chef Boxes on winning the Chef Masters Competitions. Chef Boxes are the main source of Chef Cards, Appliance Cards and Dish Cards. You can also collect a free Daily Chef Box and you have an option to purchase Chef Box by using Cash.
Chef Boxes contain Chef Cards, Dish Cards, Appliance Cards, Coins and Goodies. These cards can be used to train your Chefs, improve your dish strength and upgrade appliance which in turn helps you earn more coins and XP in your restaurant.