Minn. Stat. § 580.05: ATTORNEY TO FORECLOSE; RECORD OF POWER.

When an attorney at law is employed to conduct such foreclosure, the authority of the attorney at law shall appear by power of attorney executed and acknowledged by the mortgagee or assignee of the mortgage in the same manner as a conveyance, and recorded prior to the sale in the county where the foreclosure proceedings are had. If such attorney be employed on behalf of such mortgagee or assignee by an attorney in fact, the attorney's authority shall likewise be evidenced by recorded power.