Chop walnuts or pecans.

Combine chopped nuts, miniature marshmallows, graham cracker crumbs, and confectioners sugar in a bowl.

In a saucepan, melt semi-sweet chocolate pieces in evaporated milk over low heat, stirring continuously until thick and smooth.

Remove the chocolate mixture from the heat.

Stir in peppermint extract.

Reserve 1/2 cup of the chocolate mixture for frosting.

Add the remaining chocolate mixture to the crumb mixture.

Stir until all crumbs are evenly moistened.

Transfer the mixture to a greased 8-inch square pan.

Press the mixture firmly into the pan.

Spread the reserved chocolate mixture evenly over the top.

Chill in the refrigerator until firm and ready to serve (approximately 30 minutes).

Cut into 1 x 2-inch pieces.

Garnish each piece with a walnut or pecan half before serving.