Almost-all-chocolate cake

This is my aunt's chocolate cake, and it's exactly the one for chocoholic like me ;)

Ingredients

• 250g dark chocolate
• 140g butter
• 210g sugar
• 3 eggs
• 3 tablespoons cocoa powder (unsweetened)
• 1 teaspoon baking powder
• 100g sour cream
• 4 tablespoons all-purpose flour

Directions

Grease a circular cake tin with butter, then add a bit of flour and let it stick to the butter. Throw away the flour in excess, and put the tin in the fridge.
Preheat oven at 150°C
Melt butter and chocolate into bath water. Let it cool a bit (it must no be cold, but just not hot ;)
Into a bowl, beat well the sugar with the eggs. Add the cocoa powder, and beat carefully. Then add the flour mixed with the bakin powder.
With a spoon, add the chocolate/butter cream, beating every time you put a couple of tablespoons into the bowl. At the very end, add the sour cream.
Take the tin out of the fridge, and fold in the cake cream. Put into the oven for about 35 min.
Let it cool properly before serving.