Cut an 18 cm circle of parchment paper to line the cake pan.
Sift the flour.
Melt the butter in a double boiler.
Preheat the oven to 170℃.
Add the sugar to the eggs in three parts, whip until you can no longer make more bubbles. The batter should fall like a ribbon when you lift the electric whisk (ribbon stage).
Mix on low for 1 minute (the texture will become smoother).
Pour in the flour all at once. Fold it in until no longer powdery, turning the bowl as you go.
Pour the melted butter into the batter over a spatula. Mix by scooping the batter from the bottom.
Line the cake pan with the parchment paper circle, pour in the batter, and bake at 170℃ for 25 minutes (it is done when a toothpick or skewer inserted in the center comes out clean).
Let cool in the pan on top of a rack.
Set aside half of the strawberries for the top decoration, then finely chop the other half.
Add the sugar to the heavy cream and beat over ice water. When it becomes like thick whipped cream, add the kirschwasser and it's done.
Slice the cake in half horizontally and make a sandwich with the cream and chopped strawberries. Spread cream around the outside surface of the cake, then decorate with the whipped cream and whole strawberries.
Dust the non wet powdered sugar over the strawberries and it's done!
Story Behind this Recipe
I read many books and came up with my own delicious sponge cake using butter and no milk.
The key to making a delicious sponge cake is to mix with an electric mixer on low for one minute at the end. My friend taught me this and since then, my cakes have gotten much better.