A method of forming an article of footwear includes injecting a first material into a first cavity of a mold assembly to form a sole assembly, injecting a second material into a second cavity of the mold assembly, a first last being suspended within the second cavity, to form an upper of the article of footwear about the first last. The upper and the sole assembly are positioned in contact with one another. The upper and the sole assembly are cured and bonded together to form an article of footwear. The article of footwear is removed from the mold assembly and from the first last and allowed to expand to a first size. The article of footwear is placed on a second last having a second size that is smaller than the first size, and heated and cooled until it shrinks to the second size.