For the avocado cake, preheat the oven to 180 °C, separate the egg and beat the egg white until stiff. Cut the avocado in half and remove the pit. Carefully scoop out the flesh of the avocado, leaving the skin whole.
Mash the flesh of the avocado and mix with the egg yolk. Add a little more sugar to taste and fold the flesh into the beaten egg. Fill the avocado shell halves halfway and place a teaspoon of plain cream in the center of each.
Fill the rest of the shell full and place another teaspoon of the cream on top. Place on a baking paper and bake the avocado cakes for about 20 minutes.