The Greatest Chocolate Cake In the World? Where?

I want to be able to bake the greatest chocolate cake just like that! No measurements, no portions and no scales. I want to know my baking stuff like the back of my hand. So far, I've gotten the best sounding recipe from Nigella but the recipe uses sour cream and I'm not really sure what good can a SOUR cream do for chocolate cake. So, take a look and lemme know if you have any idea how the sour cream works here.

Nigella's Old Fashioned Chocolate Cake:
Ingredients-

1.5 cups all purpose flour(232.5g)
1 cup sugar (250g)
1 tsp baking powder
0.5 tsp baking soda
2 tsp Vanilla extract
2 medium sized eggs
1.5 sticks unsalted butter,softened(169g)
1/3 cup sour cream (153g)

Method :
Cream all the ingredients together in a food processor and pour into a baking tin.
Put tin into preheated oven at 175 degrees celsius for 30 min.