The process that gives rise to the adrenal cortex. This process pertains to the initial formation of a structure from unspecified parts. The adrenogonadal primordium from which the adrenal cortex is formed derives from a condensation of coelomic epithelial cells (the urogenital ridge; the same structure from which gonads and kidney also originate). [ http://www.ncbi.nlm.nih.gov/pubmed/21115154 http://www.ncbi.nlm.nih.gov/pubmed/12185666 ]