Cheeseburger fans, mark your calendars - September 18th is National Cheeseburger Day, and we’re celebrating at Serious Pie Ballard! Chef ET is firing up the patio flattop with one of his favorite creations: Mishima Reserve Smash Burger topped with brown butter onions, American cheese, red eye ketchup, on Rachel’s special bun, with fries. We hope you join us in sharing our deep love of cheeseburgers at this special pop up from 11:30am to 6pm, preorder to lock it in or just on up!