Vintage Chocolate Ice Box Dessert - Unforgettable!

For years I've thought of a chocolate icebox dessert that my mom used to make. The filling was rich and creamy yet light, studded with chopped nuts and set on a tender shortbread crust. Somehow the recipe was lost over the years and when I've tried doing an online search, I find overly sweet versions filled with instant pudding and whipped topping. 
However, I recently discovered  a filling that I thought might match the one from my past. It was set on a layer of ladyfingers so I substituted a shortbread crust for our 2016 Mother's Day dessert. It was delicious and both Mom and I  believe it rivals that unforgettable dessert from long ago.
Note -- back when Mom made this dessert no one worried about using uncooked eggs. However, with today's safety concerns, simply use pasteurized eggs. (Pasteurized eggs can be purchased at most major supermarkets.)

Vintage Chocolate Ice Box Dessert   Makes one 8x8" dessert; 9 servings
Shortbread Crust
6 tablespoon cold butter, cut into chunks
3/4 cup all-purpose flour
1/4 to 1/3 cup chopped pecans

1. Line an 8x8" baking pan with foil or parchment paper so that edges of foil overlap the pan (see photo in step #4 below). Spray with pan release.
2. In a mixing bowl, using the flat blade attachment, cut the butter into the flour until mixture resembles coarse meal. (Or, use a pastry blender if preferred.)
   
   
   
3. Stir in chopped pecans.
   
4. Press mixture into the bottom of a sprayed 8x8" baking pan.
   
5. Bake in a preheated 350° oven for 12 to 15 minutes or until crust is golden brown. Cool.
   

Chocolate Filling

2 (4 oz.) bars German's® Sweet Chocolate*, coarsely chopped

3 tablespoons water

4 large eggs, pasteurized  -- separated (eggs separate best when cold but have most volume if at room temp when whipped, so plan ahead and allow egg whites to set at room temp after separating; also make sure that no yolks are present in the egg whites as the fat in the whites will interfere with proper whipping)

2 tablespoons powdered sugar

3/4 to 1 cup chopped pecans

1 cup heavy cream

Garnishes as desired: whipped cream, grated or shaved chocolate, mint leaves

1. Melt chocolate in double boiler or large stainless steel bowl set atop pot of simmering water (do not allow bottom of bowl to touch water.)
   
2. Add 3 tablespoons water and stir well to combine. Remove from heat and cool for a few minutes.
   
3. Add yolks one at a time, beating vigorously after each addition.
   
4. Add powdered sugar and nuts.
   
5. In a large mixing bowl (chilled is preferable but not mandatory), whip cream until stiff. Set aside.
   
6. In a large mixing bowl, with whisk attachment, beat egg whites at high speed until stiff peaks form. (Note -- if using the same mixing bowl as the one used for whipping cream, be sure to thoroughly wash and dry as the fat from the cream will interfere with proper whipping of the egg whites.)
   
7. Using a silicon spatula, gently fold about 1/3 of the whipped cream and 1/3 of the whipped egg whites into the chocolate mixture; continue until all of the whipped cream and egg whites are incorporated.
   
8. Top cooled shortbread crust with the chocolate mixture.
   
9. Chill 12 to 24 hours.
10. Garnish with additional whipped cream, chopped or shaved chocolate and mint sprigs if desired.

* German's® Chocolate is a dark baking chocolate with sugar added for convenience; it was created in 1852. It is sweeter than semi-sweet chocolate and contains a blend of chocolate liquor, sugar, cocoa butter, flavorings, and lecithin.

Recipe without photos . . .

Vintage Chocolate Ice Box Dessert   Makes one 8x8" dessert; 9 servings

Shortbread Crust
6 tablespoon cold butter, cut into chunks
3/4 cup all-purpose flour
1/4 to 1/3 cup chopped pecans

1. Line an 8x8" baking pan with foil or parchment paper so that edges of foil overlap the pan (see photo in step #4 below). Spray with pan release.
2. In a mixing bowl, using the flat blade attachment, cut the butter into the flour until mixture resembles coarse meal. (Or, use a pastry blender if preferred.)
3. Stir in chopped pecans.
4. Press mixture into the bottom of a sprayed 8x8" baking pan.
5. Bake in a preheated 350° oven for 12 to 15 minutes or until crust is golden brown. Cool.

Chocolate Filling

2 (4 oz.) bars German's® Sweet Chocolate*, coarsely chopped

3 tablespoons water

4 large eggs, pasteurized  -- separated (eggs separate best when cold but have most volume if at room temp when whipped, so plan ahead and allow egg whites to set at room temp after separating; also make sure that no yolks are present in the egg whites as the fat in the whites will interfere with proper whipping)

2 tablespoons powdered sugar

3/4 to 1 cup chopped pecans

1 cup heavy cream

Garnishes as desired: whipped cream, grated or shaved chocolate, mint leaves

1. Melt chocolate in double boiler or large stainless steel bowl set atop pot of simmering water (do not allow bottom of bowl to touch water.)
2. Add 3 tablespoons water and stir well to combine. Remove from heat and cool for a few minutes.
3. Add yolks one at a time, beating vigorously after each addition.
4. Add powdered sugar and nuts.
5. In a large mixing bowl (chilled is preferable but not mandatory), whip cream until stiff. Set aside.
6. In a large mixing bowl, with whisk attachment, beat egg whites at high speed until stiff peaks form. (Note -- if using the same mixing bowl as the one used for whipping cream, be sure to thoroughly wash and dry as the fat from the cream will interfere with proper whipping of the egg whites.)
7. Using a silicon spatula, gently fold about 1/3 of the whipped cream and 1/3 of the whipped egg whites into the chocolate mixture; continue until all of the whipped cream and egg whites are incorporated.
8. Top cooled shortbread crust with the chocolate mixture.
9. Chill 12 to 24 hours.
10. Garnish with additional whipped cream, chopped or shaved chocolate and mint sprigs if desired.

* German's® Chocolate is a dark baking chocolate with sugar added for convenience; it was created in 1852. It is sweeter than semi-sweet chocolate and contains a blend of chocolate liquor, sugar, cocoa butter, flavorings, and lecithin.