Al Kooper's Backstage Passes and Backstabbing Bastards
says right there on page 82 that Cream's American debut was a ten day stage show starting March 25, 1967, called "Murray the K's Easter Rock Extravaganza." He recounts an exchange between himself and Cream member Ginger Baker, asking "What do you think of America so far?" Baker replied, "How the f--k should I know? I've only been 'ere thirty-five f--king minutes, 'aven't I?" Kooper reports that their relationship went uphill from there: "By the last night of the show, we were throwing eggs and whipped cream at each other, that old American rock 'n' roll ritual that denotes mutual respect."