Whisk heavy cream until stiff peaks form in a large mixing bowl with a hand or stand mixer. Then set it aside. Break Toblerone into pieces and put them in a saucepan. Melt the chocolate over low heat, regularly stirring to avoid burning. You can also use the double boiler method; place a mixing bowl with the chocolate in a hot water bath and let the Toblerone melt.
While the chocolate is melting, with a hand mixer, beat the eggs and powdered sugar in a large mixing bowl until fluffy and lighter in color. It takes about 5-10 minutes.
After the chocolate is melted, pour it into the egg mixture and mix it with a rubber spatula until fully incorporated.
Then carefully fold the heavy whipped cream into the chocolate mixture. Don't overmix it; you want to keep the mousse light and airy.
Fill the mousse into a pastry piping bag with a round tip and pipe it into small glass jars. If you don't have a pastry piping bag use a zip lock bag and cut off the tip. Cover the glass jars and place them in the refrigerator for at least 4 hours for the mousse to set. Then decorate them with a whipped cream rosette, dust them with chocolate powder, and add some chocolate sprinkles.
If you prefer to serve the mousse scooped on a plate instead of filling it into individual glass jars, cover the bowl with the mousse with plastic wrap and place it in the refrigerator for at least four hours. Preferably overnight.
Once the mousse is set, use an ice cream scoop or a tablespoon to scoop the mousse onto a dessert plate. Decorate with heavy whipping cream, fruit, chocolate powder, and chocolate sprinkles.