Start by making an egg cream: Whisk eggs and sugar with an electric mixer in a large bowl. Stop when it thickens/froths and becomes white.
Add the spices, baking powder, wheat flour, and oil while whisking vigorously to avoid lumps. You can also place a sieve over the bowl before pouring in the flour, which also helps prevent lumps.
Grate your zucchinis and add them to the mixture along with chopped walnut kernels. Stir well to evenly distribute.
Line a small baking pan with parchment paper (mine was about 28x28 cm) and pour the cake mixture into it.
Bake it in a standard oven for about 40 minutes at 175 degrees Celsius (347 degrees Fahrenheit).
Remove it from the baking pan when it comes out of the oven and place it to cool on a rack.
Mix cream cheese, powdered sugar, softened butter, and vanilla sugar together in a bowl.
Use an electric mixer to whip the mixture until smooth and creamy.
Once the cake is cooled, apply the cream cheese frosting.
Chop walnuts and sprinkle them on top.
Enjoy.
