Using an electric mixer, beat egg yolks with sugar until lemon colored. Add melted chocolate and coffee. Set aside.

Using an electric mixer (in a clean bowl), beat egg whites until stiff. Add to yolk mixture and fold to combine. Refrigerate until ready to layer.

Using an electric mixer, beat three whole eggs and three egg yolks with one cup of sugar until fluffy. Add lemon juice, and mix to combine.

Transfer to a double boiler and cook for 20 minutes, until mixture thickens. Set aside to cool completely.

Using an electric mixer (in a clean bowl), beat three egg whites with remaining three tablespoons sugar until stiff peaks form. Fold egg whites into the cooled lemon mixture.

To assemble, layer the two mousses in individual serving dishes. Keep in freezer until ready to serve.

Preheat oven to 350 degrees Fahrenheit. Grease a 9×13-inch baking pan.

In a large bowl, whisk together eggs, sugar, cocoa, oil, walnuts, and potato starch. Add to prepared baking pan and bake for 35 to 40 minutes. Let cool. Once cool, place in freezer for about two hours.

Using an ice cream scoop, scoop balls from the cake. Refreeze balls.

Melt chocolate over a double boiler. Coat balls in chocolate and top immediately with toppings. Store in freezer until ready to serve.