1. Add meringue powder and water (or just egg white) in a large bowl, using an electric mixer, beat until stiff peaks form. Then gradually add sugar, beating constantly until the meringue is thick and glossy. Then add confectioners sugar (mixed with corn starch) and mix to combine evenly.
2. Preheat the oven to 115C degree. Line a baking tray with parchment paper. Use a pipe with a 1-1.5 cm circular tip. Pipe the mix into 6 to 7cm flat discs and small domes as shown on the picture. Make 4 sets of 1 disc + 1 dome. Transfer the baking sheet to your oven and bake it for 2 hours. Remove from the oven and let it cool to room temperature. Set aside.
3. Meanwhile prepare the chocolate topping : Place a parchment paper on top of a baking sheet.
Place the chocolate in a small pot and heat until hot. Remove from the heat and stir the chocolate thoroughly until melted and smooth. Pour chocolate onto the parchment paper and immediately spread the chocolate out thinly using a spatula or the backside of a spoon.
4. Put the chocolate in the refrigerator or freezer until set (about 30 min). Remove the chocolate from the refrigerator and break it up into small pieces, using the parchment paper. Return to the refrigerator until use.
5. Once the meringue is ready, start making the cream : place the cream, sugar in a bowl and whisk until firm. Finally mix with mascarpone.
6. Now we put it all together : Put the cream on the meringue discs and then cover them with the meringue domes. Then coat the cream all around the meringue sets. Sprinkle the chocolate pieces around your cake. Put to the refrigerator until you serve.
Note : You can also make some colored meringue at the same time for decorating the tower.