knife ec2 server create doesn't have anything to support this functionality. I want to launch 4 instances and push the recipes at the time of creation only.
No, you just call it 4 times. The knife cloud tools are intentionally simplistic and are really only for very simple toy infras or learning Chef. For managing "real" systems you'll want something more full-featured (and also more complex) like Terraform or CloudFormation/SparkleFormation.