MissouriRetail Knoebel finishes work on St. Louis-area Mellow Mushroom pizzeria February 20, 2019 Share on Facebook Share on Twitter Share on LinkedIn Share via email The new Mellow Mushroom pizzeria in Cottleville, Missouri, is complete and open, with Knoebel Construction having served as the general contractor. Each Mellow Mushroom restaurant is locally owned and features a unique design. This 5,400-square-foot location features ‘80s inspired design elements and decor, neon lights, graffiti art and sculptures. The architect was Oculus Inc. The new location opened last week and is the second Mellow Mushroom in the St. Louis area. In 2016, Knoebel Construction built Mellow Mushroom in Sunset Hills, Missouri.