Chocolate Mousse Torte - Pesach

For the torte: Beat egg whites until frothy. Slowly add 1/2 cup sugar, 2 tablespoons at a time, until whites hold a good peak but are not dry. Set aside.
Beat egg yolks in large bowl until very thick and lemony in color, about 10-15 minutes. Add butter, 1 cup sugar and melted chocolate. Beat 2 minutes. Fold in beaten egg whites. Remove 1 cup of this mixture and refrigerate.
Fold ground nuts, flavoring and cake meal into remaining mixture. Pour into prepared pan. Bake 45 minutes or until cake begins to pull away from sides.
Remove from oven and cool for 15 minutes. Remove sides of pan. Let torte cool completely before inverting onto serving platter. Remove wax paper and spread reserved cup of chocolate mixture evenly over the top. Refrigerate, covered, 6-8 hours or overnight.
Pre-heat oven to 350.
Make the meringue. Combine 1 teaspoon potato starch with 1 tablespoon sugar and 1/4 cup water in small saucepan. Bring to a boil to thicken. Let cool.
Beat egg whites. When whites form soft peaks, add 1/4 cup sugar, 1 teaspoon at time. Add boiled sugar mixture and continue beating until it holds stiff peaks. Spread over top and sides of torte. Place in oven for 10 minutes to brown. Turn off oven and leave torte in oven for 5 minutes. Refrigerate until serving time.