Layered Mint Chocolate Fudge

1 12 ounce package semi-sweet chocolate chips
1 14 ounce can sweetened condensed milk
2 teaspoons vanilla extract
1 cup mint chocolate chips

In heavy saucepan, over low heat, melt chips with 1 cup sweetened condensed milk; add vanilla. Spread half the mixture into wax paper-lined 8 or 9 inch square pan; Chill 10 minutes or until firm. Hold remaining chocolate mixture at room temperature.

In heavy saucepan, over low heat, melt mint chips with remaining sweetened condensed milk. Spread on chilled chocolate layer; chill 10 minutes longer or until firm.

Spread reserved chocolate mixture on mint layer. Chill 2 hours or until firm.