In a large bowl, whip egg whites until stiff peaks form. Slowly add the sugar while beating the egg whites on low speed.
In a medium bowl, blend the ground hazelnuts with the Jell-O Pudding-Instant Vanilla
With the use of a spatula, carefully fold in the hazelnuts / Jell-O Pudding-Instant Vanilla mixture with the egg whites.
Fill a pipping bag fitted with a large round nozzle and pipe stripes from one side of the baking tray to the other side, pipe each stripe close to each other.
Bake in the middle of the oven for about 20 min, or until set.
Let the meringue cool completely.
While meringue is cooling, drain the mandarin slices. Make sure they are dry before being putting it on the cake.
In a bowl, whip up the heavy cream, powdered sugar and vanilla until it thickens.
Flip the cake upside down onto a new sheet of parchment paper. Carefully peel off the parchment paper spread the whipped cream over the bottom of the cake. Place the mandarin slices e on top of the cream.
Place the long side of the cake in front of you and start rolling it. I find using the parchment paper and a silicon mat underneath helps the rolling ones you get started, hold on to the paper rather than the cake. Once rolled up make sure the edge of the roll is facing down.
Melt the chocolate and drizzle on top, when the chocolate is firm, dust the top with icing sugar and some dark cocoa powder.