For Dave and Megan Miller, marriage isn’t all rainbows and butterflies.It’s pie and coffee.The couple is the brains behind Bang Bang Pie & Coffee, a circus-themed, roving food truck that doles out delicacies to the hungry commuter crowd.A suggested $3 donation gets you a thick slice of pie with a crust so crumbly and divine you’d think the Millers churn their own butter — and they do.Megan’s recipes are a combo of her great-aunt Lillian’s and her own. Daily flavors include triple citrus, seasonal peach, sugar cream, and smothered chocolate with the faintest trace of Jo Snow fig-vanilla-black pepper syrup. They always sell out.Dave (former Dark Matter roaster) roasts his own Bang Bang blend, which comes packed with cream, sugar, vanilla, and cinnamon.Their goal is to open a storefront. Until then, help them out on Kickstarter.Or, heck, order some pie.Follow @bangbangcoffee on Twitter for locations.Photo: Courtesy of Bang Bang Pie & CoffeeWant more local gems? Follow DailyCandy Chicago on Twitter.