These double stacked cheeseburgers all offer the savory and sweet flavors of grilled Korean barbecue. A garlic and spring onion marinade helps build up the flavor in three different ways: stirred into a burger mix, brushed onto the patties to create a glaze, and combined with mayonnaise to create a special sauce. The burgers are formed into thin patties, placed on a baking sheet, and grilled during the week for maximum caramelization and lightness. Roasted sesame oil rounds off spicy cucumbers and strengthens the burger with extra umami.