When Paula Haney first opened the Hoosier Mama Pie Company on March 14, 2009 (Pi day, appropriately enough), she worried whether her new business could survive by specializing in just one thing. When she opened her storefront that morning and saw a line around the block, she realized she had a more immediate problem: had she made enough pie? The shop closed early that day, but it has been churning out plenty of the Chicago's most delectable pies ever since.

Since starting her career as a pastry chef at Trio, one of Chicago's top fine-dining restaurants, Haney dreamed of opening her...