A method of manufacturing a midsole for an article of footwear includes cutting a pattern of openings at least partway through a midsole with a cutting tool driven by an embroidery machine. An article of footwear includes a midsole defining a pattern of openings extending at least partway through the midsole. An inner surface of the midsole is contoured and the midsole includes upwardly-extending sidewalls. At least some of the openings extend relatively nonparallel with one another through the sidewalls and splay away from one another along longitudinal axes of the openings.