SONIC® Drive-In introduces Lil' Griller mini grilled cheese sandwiches   SONIC® Drive-In introduces Lil' Griller mini grilled cheese sandwiches OKLAHOMA CITY, 2016-Dec-29 — /EPR Retail News/ — SONIC® Drive-In (NASDAQ: SONC) is the ultimate Grilled Cheese destination with the introduction of Lil' Grillers, an innovative way to enjoy timeless comfort food. Fun-sized and bursting with the savory flavor of…