New York Consolidated Laws, General Obligations Law - GOB § 5-1105. Written promise expressing past consideration

A promise in writing and signed by the promisor or by his agent shall not be denied effect as a valid contractual obligation on the ground that consideration for the promise is past or executed, if the consideration is expressed in the writing and is proved to have been given or performed and would be a valid consideration but for the time when it was given or performed.