To prepare meringues, draw 2 (8-inch) circles on each of 2 pieces of parchment paper. Turn paper over; secure with masking tape to 2 baking sheets.
Combine 1 cup hazelnut meal, 1/4 cup sugar, milk, vanilla, and almond extract in a medium bowl; stir well. Place cream of tartar, 1/8 teaspoon salt, and egg whites in a large bowl; beat with a mixer at high speed until foamy. Gradually add 1/2 cup sugar, 1 tablespoon at a time, beating until stiff peaks form (do not underbeat). Stir one-third egg white mixture into hazelnut meal mixture. Fold hazelnut meal mixture into remaining egg white mixture.
Divide egg white mixture evenly among the 4 drawn circles; spread egg white mixture to the outside edge of each circle using the back of a spoon. Bake at 200° for 3 hours or until dry. Turn oven off, and cool meringues in closed oven at least 2 hours. Carefully remove meringues from paper.
To prepare filling, combine juice and next 5 ingredients (through dash of salt) in a small saucepan; bring to a boil. Cook 1 minute, stirring constantly until thick. Transfer to a medium bowl; cover and chill. Fold in whipped topping.
Place 1 meringue on serving platter. Spread one-fourth of filling evenly over meringue. Repeat layers two more times; top with remaining meringue. Spread remaining filling around sides. Press 1/2 cup hazelnut meal around sides of cake. Combine butter and chocolate in a microwave-safe dish. Microwave at HIGH 1 minute; stir until smooth. Spread chocolate mixture over top meringue. Cover loosely, and freeze 8 hours or overnight.
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