SONIC® Drive-In announces new seasonal treat the Holiday Mint® Master Shake™ and Master Blast®   America's Drive-In unveils a variety of treats for guests to satisfy their sweet tooth OKLAHOMA CITY, 2017-Nov-08 — /EPR Retail News/ — Tis the season to celebrate and SONIC® Drive-In (NASDAQ: SONC) is putting a spin on a traditional holiday classic with the Holiday Mint® Master Shake™…