Killer Brownie, a maker of single-serve and assorted brownies, has announced plans to invest up to $1 million to expand its manufacturing plant in Miamisburg, OH. According to sources, the company is planning to add a 10,500 sq ft facility adjacent to its existing 27,000 sq ft plant, adding both office space and an R&D centre. Commenting on the move, Killer Brownie chief operating officer Matt Ross said: “We need …