This is my mother's recipe. She adapted it from a recipe called Peppermint Surprise that she found in the Pinch of Salt Lake cookbook. Here's the recipe with her changes:
2 cups crushed chocolate wafers (I grind them up in my food processor. I couldn't find the traditional chocolate wafers that we usually use, so this time I made my sister Maggie scrape the cream filling off a bag of Oreos.)
5 Tbs butter, softened
1 half-gallon peppermint ice cream, softened slightly
2 1-ounce squares unsweetened chocolate
1/2 cup butter
3 egg yolks, beaten
1 1/2 cups powdered sugar
1 Tbs vanilla extract
1/2 cup chopped pecans (optional)
3 egg whites
Combine wafer crumbs and butter in a medium-size mixing bowl; reserve 1/4 cup for topping (I skip this step and use all the crumbs for the crust.) Press into the bottom of a 9x13 pan. Spread ice cream over and freeze.
In a medium size saucepan melt chocolate and butter over low heat. Remove from heat and gradually add beaten egg yolks, stirring continuously. Add the powdered sugar, vanilla and nuts. Mix together and cool thoroughly. Beat egg whites until stiff and fold into cooled chocolate mixture. Spread over ice cream layer, sprinkle with reserved crumbs and freeze. Allow to soften slightly before cutting into squares and serving.
A couple hints with this recipe- this last time I put the crust in the freezer for 30 minutes before I spread the ice cream, that made it easier to spread. Also, heat the chocolate VERY slowly. I almost always screw the sauce up once and have to start over. This time I screwed it up TWICE. I probably should have just pulled out the double boiler. This fudge sauce can't be beat. I also always make sure to prepare this the night before I plan to serve it, so it has plenty of time to harden. I love this recipe!