When the first people in line for your store’s grand opening drove from Rock Island, Ill. and got there over an hour before the doors opened, you know you’re on to something. Not that  Scratch Cupcakery had any reason to doubt. The Cedar Falls-based bakery opened its Coralville location at 10 a.m. Tuesday at the Iowa River Landing, 927 E. 2nd Ave. This is the fourth location to open in just three years. By 11 a.m., they had given away all of the 100 free “Oh Happy Day” flavored cupcakes - vanilla with sprinkles - they’d set aside for their first customers. “It’s been quite an adventure,” owner Natalie Brown, 34, said. “It shows us our hard work has paid off.” She started Scratch as a tiny bakery, now known as Little Scratch, in Cedar Falls in June 2010. Since then her business has exploded in popularity, first moving to a bigger Cedar Falls store, then opening additional locations in Waterloo and West Des Moines. The fixed locations operate alongside a mobile truck that brings mini-Scratch locations to towns across the state. West Branch High School seniors Kara Rex, 17, and Emily Corr, 17, were at the opening. Corr had tried the cupcakes in Cedar Falls. That was enough to convince the girls to spend their free period on a cupcake excursion. “I’m really excited; they’re really delicious,” Corr said. She is not alone. With over 41,000 Facebook followers and the occasional problem --  a good one to have -- of selling out of cupcakes at her various stores, Brown said she can’t quite believe how much her life has changed since 2010, when she quit her marketing job to try her hand as a small business owner. At first she and her small team were working around the clock to keep up with demand. Now she has a staff of around 150 people, including about 40 in Coralville. Her success  is due in part to good timing. Cupcakes are hot now, but when Brown opened she was aware of only two cupcake companies in the entire state. Now, there are more than a bakers dozen. In the corridor alone, there's the Chicago-based Molly’s Cupcakes in Iowa City, which has plans for a North Liberty location, That One Cupcake Place at NewBo City Market, Take the Cake Gourmet Cupcakery in Marion and the Wright Touch Cupcakery and Catering in Cedar Rapids. Brown said Coralville has been on her radar since Scratch’s early days. Iowa River Landing organizers asked if she’d be interested just a few months after her first storefront opened. Adding Coralville as her fourth location made sense, she said. “Coralville was a no brainer for us. We like being part of what’s new and exciting and different,” she said. “We get to be a part of what’s happening there, and that part is fun for us too.” Coralville Mayor Jim Fausett stopped by the opening. The people standing in line for cupcakes justified the investment the city has put into the development, he said. “This is just another example of how popular this area is going to be,” he said. “In the next five years this area will be unbelievably changed.” Scratch is part of a slowly growing list of shops and eateries at the development, which also houses Von Maur, the Corallville Mariott Hotel and Conference Center, Vesta and Backpocket Brewing, among others. While Brown said she has a few ideas for future developments, including some, “a little outside of the box,” for now she wants to focus on making sure Scratch’s four locations are doing things right. “Last Thanksgiving and Christmas we had two stores, and this year we have four,” she said. “Is the expansion over? Probably not. Do we know what we’re going to do next yet? Not really. We want to ensure we continue to do it well and not just for the sake of expansion.” Scratch is open daily except Sunday from 10 a.m. to 7 p.m.