In a heavy sauce pan over low heat, melt chocolate chips, 1 cup sweetened condensed milk and vanilla.
Spread 1/2 mixture into prepared pan, chill 10 minutes or until firm. Reserve remaining chocolate mixture at room temperature.
In another heavy pan, over low heat, melt almond bark with remaining sweetened condensed milk (mixture will be thick). Stir in peppermint extract and food coloring, if desired. Spread this mixture on chilled chocolate mixture and chill 10 minutes.
Spread reserved chocolate mixture over mint layer.
Chill 2 hours or until firm.
Cut into small pieces.