Mattson served as Diamond Foods’ creative, new product, and R&D partner for over 18 years until their acquisition by Snyder Lance for $1.27 billion in 2016. Initially a commodity walnut co-op of 33 growers, Diamond Foods expanded into snack nuts to cater to consumers’ demand for substantial snacks. Mattson developed the first vacuum-roasted, glazed walnut using a patent-protected process, introduced the first dry roasted almond, and created their signature line, Cocoa Roast Almonds. The collaboration allowed Diamond Foods to evolve into a value-added snack company, leading to the creation of the Emerald brand to support their innovative product lines.