Traditional chocolate cake

Found a recipe on the web, again I have reduced the amount of butter and sugar substantially and managed to make a perfect chocolate cake.

Ingredients:
Dark chocolate 25g
Cocoa powder 40g
White sugar 3 full tablespoon + 2 egg white
White sugar 2 full tablespoon + 2 egg yolk
(The original recipe suggested using totally 100g white sugar, but I have used roughly 40g only)
Cake flour 30g (or plain flour + corn flour and the ratio is 2/3 to 1/3)
Unsalted butter 20 to 30g (The original recipe suggested 60g)
Cream 50g (room temperature)

Steps:
1. Beat butter until creamy.
2. Mix melted chocolate with butter.
3. Mix cocoa powder with cream.
4. Pour (3) into (2) and mix together.
5. Add cake four into (4).
6. Beat white sugar and egg white until stiff with an electric mixer.
7. Beat white sugar and egg yolk until the colour has turned light yellow.
8. Pour (7) into (6) and mix together.
9. Pour (8) into (5) and mix together.
10. Bake in a pre-heated oven at 200 degrees for 40 mins.