Line a 13x9-in. Baking pan with foil, letting ends extend over sides by 1 in. Grease the foil with 1-1/2 teaspoons butter; set aside.

In a large saucepan, combine the chocolate chips, milk, and remaining butter.  Cook and stir over medium heat until mixture is smooth.

Remove from the heat; stir in peanuts. Place marshmallows in a large bowl; add chocolate mixture and stir well. Spread into prepared pan. Sprinkle with additional peanuts and marshmallows. Refrigerate until firm.

Using foil, lift fudge out of pan. Cut into 1-1/2-in. Squares.